Avalanche Advisory Archive Pre-2016
Date Issued: | 2013-02-20 |
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Danger: | 2 |
Trend: | 4 |
Probability: | 4 |
Size: | 2 |
Problem: | 0 |
Discussion: | The National Weather Service Forecasts- TODAY...RAIN...MIXED WITH SNOW IN THE MORNING. SNOW ACCUMULATION TO 2 INCHES...MAINLY IN TAKU INLET. HIGHS AROUND 39. SOUTHEAST WIND 10 TO 20 MPH. GUSTS TO 30 MPH IN THE MORNING. TONIGHT...RAIN...CHANGING TO SNOW LATE. SNOW ACCUMULATION AROUND 1 INCH. LOWS AROUND 32. SOUTHEAST WIND 5 TO 15 MPH. THURSDAY...SNOW IN THE MORNING. RAIN. SNOW ACCUMULATION TO Temperatures have been relatively constant for the last 48 hours hovering just below freezing at the Mt Roberts Tram Summit and -1.5-2.5c at the Eaglecrest Summit. Where winds were calm over the weekend they picked up yesterday in the afternoon. Overnight we saw winds from 20-50 in our mountain zones. Douglas Island saw the bigger winds than along the channel. We received 11mm (.4) of precip overnight and 20mm(.8\")in the last 48 hours. This left us 15cm of new snow at the Mt Roberts Tram Summit. With Considerable loading winds, moderate precip accumulations and near freezing temperatures avalanche danger is MODERATE at this time. Todays forecast calls for temps remaining nearly the same until evening with slight cooling overnight. The forecast calls for as much as another .75\" of precip in the next 24 hours which could being 6+\" of new snow in our mountain enviroment. This will bring a slight rise in avalanche danger over the next 24 hours. Natural avalanches are unlikely today yet possible. The current snowpack is supporting weight well yet with wind loading and near critical precip rates the chance of natural avalanches remains. Human triggered avalanches are likely today. Be careful in areas where windloading exists. Be aware cornices will be weak. Lee slopes just below summit and ridgeline will also be building slabs quickly. Be aware of terrain traps, steep convex rolls, unsupported slopes. Ride with your partners and make sure to ride one at a time through avalanche prone terrain. Use caution and have a great day! |
Tip: | Soft Slabs: Although soft slabs are defined to be slabs less than 30 percent water weight (300 kg/m3), there is a rather fuzzy boundary between hard slabs and soft slabs. We generally think of soft slabs as composed of new snow while hard slabs are usually composed of old, denser layers of snow or very wind-hardened new snow. Also, soft slab avalanche debris tends to be soft and powdery while hard slab debris often contains chunks hard snow. The most important distinction for people in avalanche terrain is that soft slabs tend to break at or near your feet while hard slabs tend to break above you, making them much more difficult to escape being caught. |