Eastern Sierra avalanche advisory
Posted March 12, 2010 by Sue Burak
For the mountains west of Bishop to the June Mountain area, the avalanche danger rating for today LOW. Avalanche conditions are generally safe. Watch for unstable snow on isolated areas such as steep, convex, wind-loaded slopes near ridge crests, and give cornices a wide berth when travelling on or below ridges.
This information does not apply to developed ski areas or highways. This advisory describes general avalanche conditions and local variations always occur.
Winter returns today and tomorrow with perhaps the last gasp of the winter. Yesterday was a little cool to be spring but it sure was nice to be out in warmer weather and only light breezes. Clearings in the tree had a sticky layer of surface melt that froze into a thick crust by mid afternoon. Stability tests from Bishop Creek north to June Mountain all showed a stable snowpack, even off ridgetops on recent wind loaded convex pillows. We just could not get anything to move.
A party on Table Mountain Yesterday on southerly aspects found good skiing conditions on southerly aspects. An area off the Sherwin Crest had been windblasted by north winds but ski cuts did not get anything to move. Shaded, protected slopes hold the coldest snow and some high elevation terrain has boot top powder.
The incoming storm will increase the avalanche danger and triggering avalanches will become easier on Saturday and Sunday. An update will be issued Saturday morning.
Winter returns this afternoon with one more fast moving winter storm before a long dry period. A wind advisory is in effect from 1 PM today to 4 AM Saturday morning. Strong gusty winds will harass motorists on 395 and 80 mph winds will scream across the Sierra Crest.
New snowfall amounts could add up to over a foot of new snow above 9500 ft from the Mammoth area north. The town of Mammoth could pick up 8-10”. The mountains west of Bishop will be mostly shadowed out from any new snow. This will be another high intensity, short duration storm with snow falling in a 6 hour period. Scattered showers are expected Saturday morning, followed by gusty northwest winds once the front moves south. Winds will be from the north by Saturday afternoon.
Highs today will be in the upper 20’s above 9,000 ft and the mid 30’s at the 8500 ft elevation. Southwest winds will pickup this morning and increase to wind advisory levels by early afternoon.Please note that the avalanche danger rating in this advisory expires in 24 hours. This advisory is our best interpretation of snow pack conditions and NWS forecasts issued today. Backcountry travelers should be aware that elevation and geographic distinctions are approximate and that a transition zone exists between upper and lower elevations. Avalanches do not happen by accident and most human involvement is a matter of choice not chance. Most avalanche accidents are caused by slab avalanches that are triggered by the victim of member of the victim's party. Even small slides can be dangerous. Always practice route finding skills and carry avalanche rescue gear. Remember that avalanche danger ratings are only general guidelines. Distinctions between geographic areas, elevations, slope aspects and slope angles should be made.
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