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Tom Alena Seth Bonnett Cindy Brisson Dave Cox Ken Huff Nate Poore Kathy Rossman Jerry Roth Valerie L. Thomas
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Snow Pit:
After data collection was completed on the ice, each group dug a snow pit at the southern edge of the lake. Information was gathered from the snow pit using proper protocols. First, placing a meter stick at the base of the excavation and measuring to the top of the snow surface determined thickness for the snow pit. Once this was done, the layers of the snow pack were determined. This was accomplished by running one’s finger down the snow pack until resistance was encountered. Golf tees were placed at each layer interface. Next, the temperature gradient was determined by placing thermometers in each layer of the snow pack. All of this data was recorded. Density was determined using density tubes, whose empty mass was measured using a scale. The tubes were inserted in each layer of the snow pack, then removed and re-massed on the balance. The density was calculated using the difference in mass and the calculated volume of the cylinders. Lastly, the grain size and shape of the snow crystal in each layer was determined by closely examining the crystals through an 8x magnification loop.
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SNOWPIT at CASCADE LAKE
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February 18, 2002
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| GPS MEASUREMENT |
Lat. - 44°14'09"N |
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Long. - 73°51'48" W |
| ELEVATION |
639m |
| SNOWPIT DEPTH |
1.19m |
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DATA: DENSITY-TEMPERATURE PROFILE
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| Snow Layer (#) |
Tube (#) |
Weight Empty (g) |
Weight w/snow (g) |
Snow Mass (g) |
Snow Density (g/cm3) |
Thermometer (#) |
Non - Corrected Temp (°C) |
Thermometer Adjustmant (°C) |
Corrected Temp (°C) |
| 1 |
1 |
299 |
462 |
163 |
0.32 |
1a |
-2.5 |
0 |
-2.5 |
| 2 |
2 |
297 |
452 |
155 |
0.31 |
2a |
-2.8 |
0 |
-2.8 |
| 3 |
3 |
294 |
440 |
146 |
0.29 |
3a |
-3.0 |
0 |
-3.0 |
| 4 |
4 |
296 |
443 |
147 |
0.29 |
4a |
-2.1 |
0 |
-2.1 |
| 5 |
5 |
294 |
444 |
150 |
0.30 |
5a |
-3.1 |
0 |
-3.1 |
| 6 |
6 |
300 |
460 |
160 |
0.32 |
6a |
-4.5 |
+2 |
-2.5 |
| 7 |
8 |
292 |
414 |
122 |
0.24 |
7a |
-4.8 |
+2 |
-2.8 |
| 8 |
10 |
292 |
386 |
94 |
0.19 |
9a |
-6.9 |
+2 |
-4.9 |
| 9 |
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5d |
-7.8 |
-0.1 |
-7.9 |
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Snowpit Statigraphy
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| Depth (cm) |
Layer (#) |
Crystal Type |
| 119 |
7 |
stellar crystals |
| 100 |
6 |
rounded crystals 1-2mm |
| 89 |
5 |
rounded, sandy crystals |
| 69 |
4 |
ball and stick crystals, clumps to 5cm |
| 60 |
3 |
similar to above structure, somewhat smaller |
| 30 |
2 |
very rounded |
| 0 |
1 |
Lake Ice |
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Conclusions from Snow Pit at Cascade Lake:
Several items of discussion resulted from the data collected at Cascade Lake. First, we noticed a temperature trend in the layers down the snow pack. The temperature is lowest at the top of the snow pack, and warmest at the bottom. This is a result of the thermal effect of the snow. The top layers of snow insulate the layers beneath it, resulting in a warmer temperature at the bottom. Another trend is that the density of the snow increases with depth. This is a result of several factors. The main factor is that the old snow, the snow at the bottom of the snow pack, is being compacted by the pressure of the layers above it. This causes it to be more dense.
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