Good morning, this is Sue Burak for the Inyo National Forest Eastern
   Sierra Avalanche Center with an avalanche advisory for Monday, February
   9, 2009.

   MOUNTAIN WEATHER

   The National Weather Service posted an winter weather advisory last
   night for over a foot of snow above 8,000 ft. And indeed, there is 10
   inches of new snow this morning from the Mammoth Lakes Basin north
   along the crest to the Sonora Pass area. Rock Creek and areas south
   picked up 5-7 inches of snow in a few hours.

   The winter weather advisory expires at 10 AM this morning. The storm
   departs rapidly today but the strong southwest winds will continue
   throughout the day. Southwest winds will continue to be strong from the
   base of the mountains to the Sierra Crest an will shift to the west and
   northwest later today.Expect a windy day today in the mountains, with
   steady wind speeds around 30 mph and gusts to 60 mph.

   Cold air associated with this storm will keep temperatures cool today.
   Morning lows are in the single digits and the 8,000 to 9,000 ft
   elevations might not reach 20 F today. Higher elevations will be cold
   with highs around 10- 12 F. Tuesday will be about 5-8 degrees warmer,
   then temperatures will fall again as a Gulf of Alaska storm drops south
   into eastern California.

   SNOWPACK AND AVALANCHE DISCUSSION

   After a relatively calm storm that dropped up to 20 inches of snow,
   very strong south and southwest winds hammered the mountains north of
   Bishop yesterday and last night. Wind transported snow has been the
   most recent change forced on our snowpack Sunday and today. Also
   remember strong northeast winds began on Saturday, and with lots of
   fresh storm snow to move around, piled snow into drifts and slabs onto
   southerly and easterly slopes.

   Sundays very strong winds blew snow into big plumes that jetted off the
   ridgetops and slopes all the way down to the base of the mountains. The
   wind is the most important weather factor for avalanche danger today.
   Northeast winds blew hard Friday into Saturday, then the wind direction
   shifted to the southwest. Based on the patterns of wind drifted snow I
   saw on Sunday, both north and east to southeast slopes have wind
   drifted snow and wind slabs. In a dry year like we are having, there is
   not much snow on southerly aspects but east facing slopes from Convict
   Lake north are skiable and windloaded.

   In the Tioga Pass area, strong southerly winds blew from the south and
   southeast on Saturday and wind directions changed to the west and
   northwest on Sunday, loading north and northwest facing slopes above
   9,500 ft.

   Winds yesterday and this morning blew hard from the base of the
   mountains to the ridgetops. This is a different pattern than our usual
   strong ridgetop winds that form wind slabs and drifts near the top of
   high exposed ridges. Cross loading occurred yesterday in the mid
   elevation gullies along the Sherwin Ridge, in the Negatives and up the
   South Fork of Bishop Creek.

   The main avalanche concern today is new wind slabs. Hard wind slabs
   could have formed in the first few hours of high winds and could be
   covered by soft slabs. The air was humid enough to form denser and
   stiffer wind slabs than we usually get here. These wind slabs can
   propagate a long way.

   These drifts and slabs will be sensitive to the weight of a person.
   During your windy travels today, poke at any fresh drifts you come
   across that are in low angle and/or safe terrain to get a feel if they
   crack easily.

   The secondary avalanche concern is buried weak snow that has formed on
   top of the layer or crust that formed during last weeks wet snow storm.
   Avoid shallow, rocky areas, where the weak layers may collapse from the
   weight of a human.

   BOTTOM LINE

   For today, the avalanche danger rating for alpine terrain above 9,500
   ft is HIGH. This danger rating applies to east to northwest facing
   terrain steeper than 30 to 35 degrees. The avalanche danger rating in
   steep, cross loaded terrain above 8,000 ft is HIGH. This danger rating
   applies to east to northwest facing slopes. The HIGH danger rating
   means natural and human triggered avalanches are likely. There are
   widespread dangerous conditions today. Exposure to avalanche terrain is
   not recommended. Extensive experience assessing snow and terrain is
   required for safe travel today

   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.