Avalanche Advisory Archive Pre-2016
| Date Issued: | 2013-04-03 |
|---|---|
| Danger: | 2 |
| Trend: | 4 |
| Probability: | 3 |
| Size: | 2 |
| Problem: | 0 |
| Discussion: | TODAY...MOSTLY CLOUDY. PATCHY FOG IN THE MORNING ISOLATED RAIN AND SNOW SHOWERS IN THE MORNING. HIGHS AROUND 46. LIGHT WINDS BECOMING SOUTHWEST TO 10 MPH IN THE AFTERNOON. TONIGHT...DECREASING CLOUDS BECOMING MOSTLY CLEAR IN THE EVENING. LOWS AROUND 29. LIGHT WINDS ... EXCEPT NORTHEAST WIND INCREASING TO 10 TO 20 MPH WITH GUSTS TO 35 MPH LATE NEAR DOWNTOWN JUNEAU AND DOUGLAS. THURSDAY ... SUNNY. LOCALLY WINDY. HIGHS AROUND 44. NORTHEAST WIND 15 TO 25 MPH WITH GUSTS INCREASING TO 40 MPH IN THE AFTERNOON NEAR DOWNTOWN JUNEAU AND DOUGLAS. Temperatures dropped below freezing in the start zones last night. But not by more than a couple of degrees celsius. New precipitation came in the form of snow, but was limited to islolated showers and locations, with most areas getting 7cm or less of new snow which has already started to settle out. Last nights cooling will help to stabilize the upper moist/crust layers of the snowpack for this morning. But once the clouds are gone and the full effects of the warm day and solar gain are in play, then caution should be taken underneath slopes with S through W aspects. There are not going to be Taku winds for transport until the snowpack has settled through another day. But up high there is still some colder snow available for transport and the danger will be increasing going into tomorrow morning. The primary danger today is superficial wet/moist slides heating during the day. The primary danger tonight into tomorrow will be new wind slab created by cold Taku winds that tend to top load many of our start zones. Avalanche Danger is MODERATE today: Natural avalanches unlikely, potentially destructive avalanches unlikely to come near or reach developed areas. Human triggered avalanches possible. Pay particular attention to the effects of the sun on slopes as the day warms. In Urban Zones normal caution is advised. Backcountry travelers should pay attention to heating around rocks and trees in addition to the sun on snow effects. When you start to see point releases and lots of rollerballs it is time to move into the shady aspects. |
| Tip: | POINT RELEASES & SLUFFS Loose snow sliding down a mountainside is called a loose snow avalanche. Small loose snow avalanches are called Sluffs. Loose snow avalanches usually start from a point and fan outward as they descend, and because of this they are also called ?point releases.? They do not have a pronounced crown, and appear to be triangular in shape starting from a trigger point. Very few people are killed by loose snow avalanches because they tend to be small and they tend to fracture beneath you as you cross a slope instead of above you as slab avalanches often do. The avalanche culture tends to minimize the danger of loose snow avalanches, sometimes calling them \"harmless sluffs.\" But, of course, this is not always the case. Houses have been completely destroyed by \"harmless sluffs,\" and if caught in one, it can easily take the victim over cliffs, into crevasses or bury them deeply in a terrain trap such as a gully. Most of the people killed in sluffs are climbers who are caught in naturally-triggered sluffs that descend from above--especially in wet or springtime conditions. Sluffs can actually be a sign of stability within the deeper snow when new snow sluffs down without triggering deeper slabs. Sluffs are usually easy to deal with but wet springtime ones can still carry a bit of force and be difficult to get out of. |
| Forecaster: | Chris Eckel |
