CA1300415C - Method of collecting, preserving and repositioning snow on a ski slope - Google Patents
Method of collecting, preserving and repositioning snow on a ski slopeInfo
- Publication number
- CA1300415C CA1300415C CA 558276 CA558276A CA1300415C CA 1300415 C CA1300415 C CA 1300415C CA 558276 CA558276 CA 558276 CA 558276 A CA558276 A CA 558276A CA 1300415 C CA1300415 C CA 1300415C
- Authority
- CA
- Canada
- Prior art keywords
- snow
- piles
- slope
- skiing
- designated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Road Paving Structures (AREA)
Abstract
ABSTRACT OF THE INVENTION
A method of collecting, preserving and repositioning snow on a ski slope whereby the slope may be placed in condition for skiing in the fall prior to the time of sufficient fall of natural snow or the arrival of freezing conditions necessary for the production of man-made snow.
A method of collecting, preserving and repositioning snow on a ski slope whereby the slope may be placed in condition for skiing in the fall prior to the time of sufficient fall of natural snow or the arrival of freezing conditions necessary for the production of man-made snow.
Description
~3(~U415 BACKGROUND OF THE INVENT~ON
Skiing on ski slopes or trails terminates in the late winter and early spring with the melting of the snow. The slopes and trails become bare over the summer months. Skiing normally rcsumcs in thc fall or early winter when sufficient snow has fallen to provide adcquate snow covcr on the slopes and trails.
In a few instances, early fall skiing has been achieved by the spreading of man-made snow but the success of this process is dependent on the arrival of nights with below freezing temperatures.
SUMMARY OF THE PRESENT INVENTION
The present invention is to a method whereby any selected ski slope or trail may be placed in skiing condition earlier in the fall then would nor~nally be the case.
Hereinafter when the term ski slope is used it will also include a ski trail. The method will be most commonly used on ski slopes.
According to one aspect of the invention there is provided a mcthod of seasonally shifting snow covcragc on a dcsignated ski slopc in ordcr to achieve skiing on said designatcd slope at a time of the year when said slope would otherwise be closed for skiing because of inadequate snow cover which method comprises at a time of the year when said designated slope could otherwise remain open for skiing, closing said designated slope; collecting the snow remaining on said designated slope into a series of piles distributed over the entire length of the slope; and, covering said piles with sheets of insulating material by placing said sheets over said piles such that they are substantially -2- ~;
'c 13~(J4~i supported by the snow in said piles; and, at a time of the year when said designated slope would otherwise be closed for skiing, uncovering said piles and distributing the snow rcmaining in said pilcs across said dcsignated slope so as to achieve a depth satisfactory for skiing thcrcon.
According to another aspect of the invention there is provided a method of seasonaily shifting snow coverage on a designated ski slope in order to achieve skiing on said dcsignated ski slope at a time of the year when said slope would otherwise be closed for skiing because of inadequate snow cover which method comprises at a time of the year when said designated slope could otherwise remain open for skiing, closing said designated slope; collecting the snow remaining on said designated slope into a series of snow piles distributed over the entire length of the slope; and, covering said snow piles with sheets of insulating material, wherein said sheets comprise two layers of aluminum foil spaced about one-quarter inch apart between which are two layers of polyethylene bubbles, by placing said sheets over said snow piles such that they are substantially supported by the snow in said snow piles; and, at a time of the year when said designated slope would otherwisc be closed for skiing, uncovering said snow piles and distributing the snow remaining in said snow piles across said designated slope so as to achieve a depth satisfactory for skiing thereon.
These piles are typically high in the center and tapering downwardly to the surrounding ground. The piles preferably will be circular. The spacing of the piles will be determined by the depth and location of the snow available.
The piles of snow are then covered with sheets of insulating material of such character. It is therefore possible that a major volume of the piled snow will be preserved 13~
over the summer and early fall months. At a time of the year when said designated slope would otherwise be closed for skiing, for example when the average ambient temperature has dropped in the fall to a degree at which the snow will not melt away, the piles will be uncovcred and thc snow redistributed, by hand and/or machine over the selected areas of the slope. The dcpth of the redistributed snow now covering the selected slope area will be satisfactory for immediate skiing, and typically will last until the arrival of natural snow. Should the arrive of natural snow be delayed, the snow base can be augmented by the application of man-made snow at the necessary locations after nighttime freezing conditions have arrived in the fall.
BRIEF DESCRIPI'ION OF THE DRAWINGS
Fig. 1 is a plan view of a snow covered ski slope.
Fig. 2 is a vertical section on the line 2-2 of Fig. 1.
Fig. 3 is a section on the line 3-3 of Fig. 2.
Fig. 4 is a plan view of the ski slope of Fig. 1 with the snow thereon pushed into a plurality of pilcs~ _ _ -/
~ ...
- 3a -, ~ l3~a4~s !' Fig. 5 is a vertical section on the line 5-5 of Fig. 4.
Fig. 6 is a section on the line 6-6 of Fig. 5.
Fig. 7 is a plan view of the ski slope of Figs. 1 and 4 with the piled snow of Figs. 4, 5 and 6 redistributed on the slope.
Fig. 8 is a vertical section on the line 8-8 of`Fig. 7.
Fig. 9 is a section on the line 9-9 of Fig. 8.
Fig. 10 is a view similar to Fig. 9 but showing the snow covering a greater area.
Fig. 11 is an enlarged view illustrating a snow pile to which man-made snow has been added.
DETAILED ~ESCRIPTION OF THE INVENTION
Fig. 1 is intended to represent any ski slope 2 which is covered with snow 4. For help in explanation o~ the invention, the snow covered area of the slope is shown as having top, side and bottom boundaries indicated at 6, 8, 1~ and 12.
Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1 showing the ground 14 with the snow 4 covering the sloping surface 2. The upper li~it of the snow with which we are concerned is at 6 and the bottom limit at 8. Fig. 3 is a section taken on the line 3-3 of Fig. 2.
It is to be understood that the representation of Fiqs. 1, 2 and 3 is intended to include any ski slope havi~g thereon snow (,natural, natural and man-made or man-made~ toward the end of the skiing season when the operator elects to close the slope.
I, - 13U~!41S -li i! I
It will be appreciated that the depth and disposition of the snow at the time the slope is closed may vary greatly depending upon the extent of the snow fall over the past winter and the configuration of the ground surface.
The snow on the slope is pushed, preferably by machines, into a plurality of piles of snow indicated at 16 in Figs. 4, 5 and 6. The location of the piles of snow on the slope will be dictated by the configuration of the slope, the depth of the snow and the judgment of the operator. The piles are made as high as possible, preferably generally circular in plan and are then covered with sheets of insulating material 18 of such properties as to be capable of preserving a major portion of the snow over the summer and early fall.
In places where the snow is deep, it may be pushed.into suitably sized p$1es without using all of the snow adjacently available. Where the snow cover is thin, it may be necessary to ;use all of the snow at that location to produce a large enough 'pile to survi.ve the summer. In all cases the object is to pre-,serve enough snow by the pïling procedure plus the insulating covering to have enough.snow available in the fall which when spread on the slope will create ade~uate s~iing conditions.
Preferably the.area of the collected snow pile should be small in relation to the area from which the snow was collected.
In ot~er words, a high pl.le on a small area is preferable to a lower pile in a larger area because the percentage loss from melting is approximately inversely proportional to the height of the pile. Snow can readily be piled by machïne to a height -- 13~)041S ~
;
of 20 feet or more at the center and s.loping to the s~ides in a circular pattern. A pi.le of snow of thi.s character covered with suitable insulating material will lose no more than 20 to 25% of its ~olume over the summer. Thus for example if there was an average of tw.o fe.et of snow on .he slope when the piling commenced and all of i.t was pushed into the piles, enough snow would remain by fall to cover the slope to an average depth more or le~s o~ one and one~half feet, adequate.for immediate skiing.
Fi.gs. 7, 8 and 9 are illustratiYe of the condition of the slope follow~i`ng di.stribution of the snow i'n the fall from the piles 16 shown in Fïgs. 4, 5 and 6. In Fig. 7, the lines 20 and 22 suggest the somewhat reduced w.idth of the slope if the original depth.is pro~i'ded whereas Fig. g suggests a width of slope corresponding to boundaries 8 and 10 of Fi.g. 1 and 3 but with a reduced dept~.determined by the extent of the melting.
It has ~een found desirable and practical in some situati.ons. t~ i`ncrease the. volume,of the preserved pile of snow by ¦
removing the. cover 18, adding man-made snow and recovering the pi.le. as sho~n in Fi.~. 11. Thi.s. procedure would be used when the resi.dual layer of snow. available.in the spring was inadequate for producing the. depth.ini.tially wanted in the fall. The,.
additi.on o~ man-~ade. sno~ can be ~ade wheneYer the temperature falls. below free:zi`ng w~lch.conditïon usually'be.gins early in the fall. Repeated addi.tions of ~an-made snow will create a pile suffici~ent w~en spread to provide skiing condi.tions on the '' 13~Q415 selected area. Fig. 11 suggests the condition existing after man-made snow 24 has been added to the initial pile of snow 16 and the covering 28 replaced.
The process of accumulating the residual snow in piles in the spring and distributing it in the fall will preferably proceed from the top to the bottom of the slope as the snow movement is aided bY gravity but this process may be varied under the judgment of the machine operator.
Insulating covering ade~uate to preserve snow over the summer is available in the open market. One such material comprises two layers of aluminum foil spaced about ~ inch between which are two layers of polyethylene bubbles. These circular flattened bubbles, about 3/8 inch in diameter are arranged so that each bubble is surrounded by six other bubbles, all bonded to themselves and to the covering layers of aluminum foil. This construction forms a strong sheet having the capability of substantially limiting passage of the sun's radiant heat and the heat of the ambient air to the snow thereunder.
The sheet may be further strengthened by a coating of clear ,polyethylene to both e~terior sides. This sheet is light, j~flexible and durable and may be readily rolled on and off each pile of snow.
`' The sheets must be firmly anchored to the ground to prevent j . , the sheets from being dislodged by the wind and also to prevent the entrance of warm air under the sheets which would cause i3t~)4~5 - , !
excessive melting of the covered snow. The sheets may be anchored for example by placing weights on the edge areas 26 or in any other manner available. The securing means must be readily removable so that the sheets can be rolled off the piles and saved for use the-following year.
In the drawings, it will be understood that the thickness of the sheets in relation to the size of the piles of snow has necessarily been exaggerated.for purpose of illustration.
It is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and the scope of the invention.
Skiing on ski slopes or trails terminates in the late winter and early spring with the melting of the snow. The slopes and trails become bare over the summer months. Skiing normally rcsumcs in thc fall or early winter when sufficient snow has fallen to provide adcquate snow covcr on the slopes and trails.
In a few instances, early fall skiing has been achieved by the spreading of man-made snow but the success of this process is dependent on the arrival of nights with below freezing temperatures.
SUMMARY OF THE PRESENT INVENTION
The present invention is to a method whereby any selected ski slope or trail may be placed in skiing condition earlier in the fall then would nor~nally be the case.
Hereinafter when the term ski slope is used it will also include a ski trail. The method will be most commonly used on ski slopes.
According to one aspect of the invention there is provided a mcthod of seasonally shifting snow covcragc on a dcsignated ski slopc in ordcr to achieve skiing on said designatcd slope at a time of the year when said slope would otherwise be closed for skiing because of inadequate snow cover which method comprises at a time of the year when said designated slope could otherwise remain open for skiing, closing said designated slope; collecting the snow remaining on said designated slope into a series of piles distributed over the entire length of the slope; and, covering said piles with sheets of insulating material by placing said sheets over said piles such that they are substantially -2- ~;
'c 13~(J4~i supported by the snow in said piles; and, at a time of the year when said designated slope would otherwise be closed for skiing, uncovering said piles and distributing the snow rcmaining in said pilcs across said dcsignated slope so as to achieve a depth satisfactory for skiing thcrcon.
According to another aspect of the invention there is provided a method of seasonaily shifting snow coverage on a designated ski slope in order to achieve skiing on said dcsignated ski slope at a time of the year when said slope would otherwise be closed for skiing because of inadequate snow cover which method comprises at a time of the year when said designated slope could otherwise remain open for skiing, closing said designated slope; collecting the snow remaining on said designated slope into a series of snow piles distributed over the entire length of the slope; and, covering said snow piles with sheets of insulating material, wherein said sheets comprise two layers of aluminum foil spaced about one-quarter inch apart between which are two layers of polyethylene bubbles, by placing said sheets over said snow piles such that they are substantially supported by the snow in said snow piles; and, at a time of the year when said designated slope would otherwisc be closed for skiing, uncovering said snow piles and distributing the snow remaining in said snow piles across said designated slope so as to achieve a depth satisfactory for skiing thereon.
These piles are typically high in the center and tapering downwardly to the surrounding ground. The piles preferably will be circular. The spacing of the piles will be determined by the depth and location of the snow available.
The piles of snow are then covered with sheets of insulating material of such character. It is therefore possible that a major volume of the piled snow will be preserved 13~
over the summer and early fall months. At a time of the year when said designated slope would otherwise be closed for skiing, for example when the average ambient temperature has dropped in the fall to a degree at which the snow will not melt away, the piles will be uncovcred and thc snow redistributed, by hand and/or machine over the selected areas of the slope. The dcpth of the redistributed snow now covering the selected slope area will be satisfactory for immediate skiing, and typically will last until the arrival of natural snow. Should the arrive of natural snow be delayed, the snow base can be augmented by the application of man-made snow at the necessary locations after nighttime freezing conditions have arrived in the fall.
BRIEF DESCRIPI'ION OF THE DRAWINGS
Fig. 1 is a plan view of a snow covered ski slope.
Fig. 2 is a vertical section on the line 2-2 of Fig. 1.
Fig. 3 is a section on the line 3-3 of Fig. 2.
Fig. 4 is a plan view of the ski slope of Fig. 1 with the snow thereon pushed into a plurality of pilcs~ _ _ -/
~ ...
- 3a -, ~ l3~a4~s !' Fig. 5 is a vertical section on the line 5-5 of Fig. 4.
Fig. 6 is a section on the line 6-6 of Fig. 5.
Fig. 7 is a plan view of the ski slope of Figs. 1 and 4 with the piled snow of Figs. 4, 5 and 6 redistributed on the slope.
Fig. 8 is a vertical section on the line 8-8 of`Fig. 7.
Fig. 9 is a section on the line 9-9 of Fig. 8.
Fig. 10 is a view similar to Fig. 9 but showing the snow covering a greater area.
Fig. 11 is an enlarged view illustrating a snow pile to which man-made snow has been added.
DETAILED ~ESCRIPTION OF THE INVENTION
Fig. 1 is intended to represent any ski slope 2 which is covered with snow 4. For help in explanation o~ the invention, the snow covered area of the slope is shown as having top, side and bottom boundaries indicated at 6, 8, 1~ and 12.
Fig. 2 is a vertical section taken on the line 2-2 of Fig. 1 showing the ground 14 with the snow 4 covering the sloping surface 2. The upper li~it of the snow with which we are concerned is at 6 and the bottom limit at 8. Fig. 3 is a section taken on the line 3-3 of Fig. 2.
It is to be understood that the representation of Fiqs. 1, 2 and 3 is intended to include any ski slope havi~g thereon snow (,natural, natural and man-made or man-made~ toward the end of the skiing season when the operator elects to close the slope.
I, - 13U~!41S -li i! I
It will be appreciated that the depth and disposition of the snow at the time the slope is closed may vary greatly depending upon the extent of the snow fall over the past winter and the configuration of the ground surface.
The snow on the slope is pushed, preferably by machines, into a plurality of piles of snow indicated at 16 in Figs. 4, 5 and 6. The location of the piles of snow on the slope will be dictated by the configuration of the slope, the depth of the snow and the judgment of the operator. The piles are made as high as possible, preferably generally circular in plan and are then covered with sheets of insulating material 18 of such properties as to be capable of preserving a major portion of the snow over the summer and early fall.
In places where the snow is deep, it may be pushed.into suitably sized p$1es without using all of the snow adjacently available. Where the snow cover is thin, it may be necessary to ;use all of the snow at that location to produce a large enough 'pile to survi.ve the summer. In all cases the object is to pre-,serve enough snow by the pïling procedure plus the insulating covering to have enough.snow available in the fall which when spread on the slope will create ade~uate s~iing conditions.
Preferably the.area of the collected snow pile should be small in relation to the area from which the snow was collected.
In ot~er words, a high pl.le on a small area is preferable to a lower pile in a larger area because the percentage loss from melting is approximately inversely proportional to the height of the pile. Snow can readily be piled by machïne to a height -- 13~)041S ~
;
of 20 feet or more at the center and s.loping to the s~ides in a circular pattern. A pi.le of snow of thi.s character covered with suitable insulating material will lose no more than 20 to 25% of its ~olume over the summer. Thus for example if there was an average of tw.o fe.et of snow on .he slope when the piling commenced and all of i.t was pushed into the piles, enough snow would remain by fall to cover the slope to an average depth more or le~s o~ one and one~half feet, adequate.for immediate skiing.
Fi.gs. 7, 8 and 9 are illustratiYe of the condition of the slope follow~i`ng di.stribution of the snow i'n the fall from the piles 16 shown in Fïgs. 4, 5 and 6. In Fig. 7, the lines 20 and 22 suggest the somewhat reduced w.idth of the slope if the original depth.is pro~i'ded whereas Fig. g suggests a width of slope corresponding to boundaries 8 and 10 of Fi.g. 1 and 3 but with a reduced dept~.determined by the extent of the melting.
It has ~een found desirable and practical in some situati.ons. t~ i`ncrease the. volume,of the preserved pile of snow by ¦
removing the. cover 18, adding man-made snow and recovering the pi.le. as sho~n in Fi.~. 11. Thi.s. procedure would be used when the resi.dual layer of snow. available.in the spring was inadequate for producing the. depth.ini.tially wanted in the fall. The,.
additi.on o~ man-~ade. sno~ can be ~ade wheneYer the temperature falls. below free:zi`ng w~lch.conditïon usually'be.gins early in the fall. Repeated addi.tions of ~an-made snow will create a pile suffici~ent w~en spread to provide skiing condi.tions on the '' 13~Q415 selected area. Fig. 11 suggests the condition existing after man-made snow 24 has been added to the initial pile of snow 16 and the covering 28 replaced.
The process of accumulating the residual snow in piles in the spring and distributing it in the fall will preferably proceed from the top to the bottom of the slope as the snow movement is aided bY gravity but this process may be varied under the judgment of the machine operator.
Insulating covering ade~uate to preserve snow over the summer is available in the open market. One such material comprises two layers of aluminum foil spaced about ~ inch between which are two layers of polyethylene bubbles. These circular flattened bubbles, about 3/8 inch in diameter are arranged so that each bubble is surrounded by six other bubbles, all bonded to themselves and to the covering layers of aluminum foil. This construction forms a strong sheet having the capability of substantially limiting passage of the sun's radiant heat and the heat of the ambient air to the snow thereunder.
The sheet may be further strengthened by a coating of clear ,polyethylene to both e~terior sides. This sheet is light, j~flexible and durable and may be readily rolled on and off each pile of snow.
`' The sheets must be firmly anchored to the ground to prevent j . , the sheets from being dislodged by the wind and also to prevent the entrance of warm air under the sheets which would cause i3t~)4~5 - , !
excessive melting of the covered snow. The sheets may be anchored for example by placing weights on the edge areas 26 or in any other manner available. The securing means must be readily removable so that the sheets can be rolled off the piles and saved for use the-following year.
In the drawings, it will be understood that the thickness of the sheets in relation to the size of the piles of snow has necessarily been exaggerated.for purpose of illustration.
It is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and the scope of the invention.
Claims (14)
1. In snow cover management at a ski area, the method of seasonally shifting snow coverage on a designated ski slop in order to achieve skiing on said designated slope at a time of the year when said slope would otherwise be closed for skiing because of inadequate snow cover which method comprises:
(A) at a time of the year when said designated slope could otherwise remain open for skiing, closing said designated slope; collecting the snow remaining on said designated slope into a series of piles distributed over the entire length of the slope; and, covering said piles with sheets of insulating material by placing said sheets over said piles such that they are substantially supported by the snow in said piles; and, (B) at a time of the year when said designated slope would otherwise be closed for skiing, uncovering said piles and distributing the snow remaining in said piles across said designated slope so as to achieve a depth satisfactory for skiing thereon.
(A) at a time of the year when said designated slope could otherwise remain open for skiing, closing said designated slope; collecting the snow remaining on said designated slope into a series of piles distributed over the entire length of the slope; and, covering said piles with sheets of insulating material by placing said sheets over said piles such that they are substantially supported by the snow in said piles; and, (B) at a time of the year when said designated slope would otherwise be closed for skiing, uncovering said piles and distributing the snow remaining in said piles across said designated slope so as to achieve a depth satisfactory for skiing thereon.
2. The method of claim 1 wherein the periphery of each of said sheets of insulating material is anchored to the ground surrounding each said pile.
3. The method of claim 1 wherein said piles of snow have a height of approximately 20 feet or more at the center.
4. The method of claim 1 wherein said designated slope is closed for skiing while there remains an average snow depth of at least about two feet thereon.
5. The method of claim 1 additionally comprising the steps of uncovering said piles of snow, adding additional snow thereto to increase the size of said piles, and recovering the piles.
6. The method of claim 1 wherein said sheets of insulating material are rolled onto each pile of snow to cover it and rolled off to uncover it.
7. In snow cover management at a ski area, the method of seasonally shifting snow coverage on a designated ski slope in order to achieve skiing on said designated slope at a time of the year when said slope would otherwise be closed for skiing because of inadequate snow cover which method comprises:
(A) at a time of the year when said designated slope could otherwise remain open for skiing, closing said designated slope; collecting the snow remaining on said designated slope into a series of snow piles distributed over the entire length of the slope; and, covering said snow piles with sheets of insulating material, wherein said sheets comprise two layers of aluminum foil spaced about one-quarter inch apart between which are two layers of polyethylene bubbles, by placing said sheets over said snow piles such that they are substantially supported by the snow in said snow piles; and, (B) at a time of the year when said designated slope would otherwise be closed for skiing, uncovering said snow piles and distributing the snow remaining in said snow piles across said designated slope so as to achieve a depth satisfactory for skiing thereon.
(A) at a time of the year when said designated slope could otherwise remain open for skiing, closing said designated slope; collecting the snow remaining on said designated slope into a series of snow piles distributed over the entire length of the slope; and, covering said snow piles with sheets of insulating material, wherein said sheets comprise two layers of aluminum foil spaced about one-quarter inch apart between which are two layers of polyethylene bubbles, by placing said sheets over said snow piles such that they are substantially supported by the snow in said snow piles; and, (B) at a time of the year when said designated slope would otherwise be closed for skiing, uncovering said snow piles and distributing the snow remaining in said snow piles across said designated slope so as to achieve a depth satisfactory for skiing thereon.
8. The method of claim 7 further wherein the polyethylene bubbles in said sheets of insulating material comprise circular, flattened bubbles arranged so that each bubble is surrounded by six other bubbles, all bonded to themselves and to the covering layers of aluminum foil.
9. The method of claim 7 additionally comprising the step of coating said sheets of insulating material with clear polyethylene applied to both exterior sides.
10. The method of claim 7 wherein the periphery of each of said sheets of insulating material is anchored to the ground surrounding each said snow pile.
11. The method of claim 7 wherein said piles of snow have a height of approximately 20 feet or more at the center.
12. The method of claim 7 wherein said designated slope is closed for skiing while there remains an average snow depth of at least about two feet thereon.
13. The method of claim 7 additionally comprising the steps of uncovering said piles of snow, adding additional snow thereto to increase the size of said piles, and recovering the piles.
14. The method of claim 7 wherein said sheets of insulating material are rolled onto each pile of snow to cover it and rolled off to uncover it.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 558276 CA1300415C (en) | 1988-02-05 | 1988-02-05 | Method of collecting, preserving and repositioning snow on a ski slope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 558276 CA1300415C (en) | 1988-02-05 | 1988-02-05 | Method of collecting, preserving and repositioning snow on a ski slope |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1300415C true CA1300415C (en) | 1992-05-12 |
Family
ID=4137399
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 558276 Expired CA1300415C (en) | 1988-02-05 | 1988-02-05 | Method of collecting, preserving and repositioning snow on a ski slope |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1300415C (en) |
-
1988
- 1988-02-05 CA CA 558276 patent/CA1300415C/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |