11 April, 2002

Today was the monthly measurements of all 11 ponds within and near the Poker Flat Research Range. We took 1 snow sample, 3 base temperature and snow depth, 3 ice thickness/freeboard, and 1 surface temperature measurements. The purpose of collecting this data is to provide a context for the data collected from the primary and secondary sites (MST, 31.6, and 33.5 Mile ponds).

Science Behind Freeboard

After drilling for ice thickness measurements, sometimes freeboard is measured. Freeboard is a measurement between the water level and ice surface. If the ice surface is above the water level, the freeboard is positive. A negative freeboard indicates flooding (ice surface below water). One main reason water floods after drilling is the weight from snow depth and snow density.

Students' comments from Howard Luke Camp field trip on March 26th:

We learned that snow is an insulator. We also collected snow samples. Some of the kids ate theirs, but I took mine home.

I learned that the snow is like a blanket, and we weighed the snow. My snow was the heaviest. It was 10 grams, and we checked the temperature of the snow and the air that we breathe. I had fun.

We put temperature things in the snow. Mine was -5.8 degrees. We made our own snow samples. I learned that snow was really warm underground than above it.

All we did was learn about snow. We used these C degrees meters, put them in snow, waited a few minutes and read how cold it was. Then we got snow samples and all it did was melt.

I stuck thermometers in the snow and we saw how the temperature in the snow changes and why. We got snow samples with tubes and hamburger flippers.

1. On 29.5-mile pond, ice fracture close to the shoreline. Some are as thick as 5 cm.

2. This pond has a positive freeboard (water below ice surface) of 11 cm, which is pretty deep compared to other ponds.

3. Flooding

4. Low water level