Avalanche Advisory Archive Pre-2016
Date Issued: | 2012-12-29 |
---|---|
Danger: | 2 |
Trend: | 4 |
Probability: | 3 |
Size: | 2 |
Problem: | 0 |
Discussion: | The National Weather Service Forecasts- TODAY...CLOUDY. A CHANCE OF SNOW IN THE MORNING...THEN A CHANCE OF RAIN IN THE AFTERNOON. HIGHS AROUND 38. SOUTHEAST WIND 10 MPH. Spatial Variability remains high. We saw more snow yesterday in town and along the channel than at the Ski Area on Douglas. This new snow is coming to rest on a snowpack that has been fairly thin and wind blasted for weeks. Some places are stripped down to shallow snowpacks. They may be seeing layers of faceting in places. Some places the snow may have drifted in in greater quantities. This has a little more insulating quality and the crystal shapes may be different in these areas. Also we still have many weak layers deeper in the snowpack that are not very supportive although they are still holding weight at this time. We received 21cm(8\") of new snow at the Mt Roberts Tram Summit in the last 24 hours. Showing a total of only about 24cm in a 48 hour period. Precip totals during this time were 20mm of precip in the last 24 hours and a total of 32mm overall. This is fairly heavy dense snow. We started the cycle with fair winds ranging from 10-35 with the highest winds coming from Eaglecrest on Douglas. This mornings winds are ranging from 10-25 and have slowed slightly. Direction remains out of the SE for the most part. Temperatures have warmed slightly since the beginning of this snowfall event and are predicted to continue to rise slowly over the next 48 hours. This is bringing us up close to the point of freezing which is often a critical trigger to go into natural avalanche cycles. Any activity we see today is not predicted to be large. As we go through the next 24 hours danger levels will increase. Precip Rates will increase, Temperatures will increase, and this questionably strong snowpack will feel the weight of quite a bit of loading during the day tomorrow into the following day. There are pockets of instability today. As we go through today into tomorrow expect those pockets to grow in size as will the avalanches they can produce. Choose your routes carefully today. Enjoy the new snow but be cautious of terrain traps. Exposed terrain, and convex unsupported slopes. HAVE A GREAT DAY. We definitely are building conditions that could lead to an avalanche. Yesterday we did not see enough new snow to really make things sensative. Today the possibility of man made avalanches is increasing. TONIGHT...RAIN LIKELY. LOWS AROUND 36. SOUTHEAST WIND 10 MPH. SUNDAY...RAIN. HIGHS AROUND 39. SOUTHEAST WIND 5 TO 15 MPH. SUNDAY NIGHT...RAIN AND SNOW. LOWS AROUND 34. SOUTHEAST WIND |
Tip: | What makes a bed surface? You don't need a bed surface to make an avalanche but it helps. Sometimes avalanches fracture within a thick layer of weak snow and the avalanche creates its own bed surface. Common bed surfaces include: Did our recent wind event create a bed surface? surely in places it did. Its old snow... its dirty snow... and in places hardened and polished off. This can be the weak layer that the avalanche fails on. Right now as we see increased load tonight into tomorrow we will also want to re-evaluate older weak layers to see if they too might become reactive once again. |