Avalanche Forecasting Exercise

It is February 15 and you are the forecaster for today. Choose the avalanche problems for the day based on the information shown below.

Weather History – The season began with a weak long storm cycle at the beginning of December.  Because the season essentially started with one big storm there are no buried persistent weak layers and the snowpack is mostly stable. The rest of December sees several small storms – stormy enough that there are no prolonged periods of high pressure – but the storms are small enough that the snowpack is still thin. At the end of the December/beginning of January, there is a prolonged dry spell with temps well below zero for over a weak. This leads to widespread faceting on mid to upper elevation slopes facing north through east. Snow returns by the second week in January and it remains snowy with medium sized storms every couple days through early February.

Based on the information shown below, what do you expect the distribution of the persistent slab problem to be?

Weather History – The season began with a weak long storm cycle at the beginning of December.  Because the season essentially started with one big storm there are no buried persistent weak layers and the snowpack is mostly stable. The rest of December sees several small storms – stormy enough that there are no prolonged periods of high pressure – but the storms are small enough that the snowpack is still thin. At the end of the December/beginning of January, there is a prolonged dry spell with temps well below zero for over a weak. This leads to widespread faceting on mid through upper elevation slopes facing north through east. Snow returns by the second week in January and it remains snowy with medium sized storms every couple days through early February.

You had reports of one natural avalanche the day prior, and your stability tests were mixed between ECTP and ECTN. How you you rate sensitivity?

Based on your previous responses to distribution and sensitivity – how would rate likelihood of the persistent slab problem?

Time to put it all together and issue a hazard rating. You know recent avalanches on the same persistent weak layer have been around size D2. Based on this, the likelihood you determined, and the weather forecast, what is your hazard rating.