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MSAC Avalanche Advisory Print E-mail

  The Mt. Shasta Avalanche Center - US Forest Service  

April 12, 2009 was our last avalanche advisory of the season.  To look at the avalanche advisories of the season, go to "Archived Advisoories" in the left column of this page, or click here.  Thanks for your support!!!  A big thank you to FMSAC for providing this new web page, paying for maintenance of our weather stations, and other budget funding!  We also thank our families for patience and support through early morning hours and long work days!

General Information Pertaining to Spring & Summer Avalanche Conditions:

Spring Time brings us the possibility of corn snow, powder or rain.  Remember it is possible for spring storms to dump impressive amounts of snow and rain.  Most of the avalanche activity associated with these spring storms occurs during or shortly after the storm event.  Timing is critical when playing in avalanche terrain.

Terrain:  Remember most of the terrain that we like to play on is greater than 30 degrees.  Avalanches are possible on anything steeper than 30 degrees, especially wet snow avalanches.  Avoid cornices, rock bands, terrain traps and runout zones of avalanche paths.

Weather:  When there are storms in the spring, they can bring impressive amounts of rain, snow and wind.  This can greatly increase the avalanche danger during and after storms.  Heed the signs: Wind (significant snow transport and depositions), Temperature (rapid/prolonged warming, which in turn weakens the snowpack), and Precipitation (Snor or rain add weight and stress to the current snowpack).

SnowpackIf snow accumulates, give the snowpack a chance to adjust to the new snow load before you play on or near steep slopes (greater than 30 degrees).  Most direct action avalanches occur within 24-48 hours of recent snowfall.  Watch for obvious signs of snowpack instability such as recent natural avalanche activity, collapsing of the snowpack (often associated with a “whumphing” sound), and shooting cracks. If you see these signs of instability, limit your recreation to lower angle slopes.

If during the warmer parts of the day you see signs that the surface snow is getting warm, such as snowballs rolling down the slope or you find the snow is sloppy enough that you sink in to your boot tops, it would probably be a good idea to play it cool and find another slope to play on or under, or call it a day. If this does happen, avalanches can be triggered.  If the snow only freezes at night, an early start will be imperative.  The snow does soften quickly and will become increasingly unstable throughout the day as it is warmed by solar radiation.  If the snow is soft early in the morning due to a lack of freezing overnight, it is probably a good idea to play another day.

Human Factor: Don’t forget to carry and know how to use avalanche rescue gear. You should NOT be skiing or climbing potential avalanche slopes without having beacons, shovels, and probes.  Only one person in a group should be exposed to potential avalanche danger at a time.  Remember, climbing, skiing, and riding down the edge of slopes is safer than being in the center.  Just because another person is on a slope doesn’t mean that it is safe.  Be an individual!  Make your own decisions.  Heed the signs of instability: rapid warming, “whumphing” noises, shooting cracks, snowing an inch an hour or more, rain, roller balls, wind loading, recent avalanche activity.

Wet slide in Avalanche Gulch on Mt. Shasta during July.Wet Slides:  While both soft slabs and hard slabs have occurred on Mt. Shasta during the spring and summer, wet slides are more common.  These types of avalanches are more difficult to predict, harder to trigger, and not as fast as other avalanches.  While wet slides are more difficult for people to trigger, many of the popular climbing routes on Mt. Shasta are in avalanche pathways.  Wet slides occur more frequently when temperatures stay above freezing for 24 hours or longer, or moderate to heavy rain falls.  Watch for:  unusually warm temperatures, sinking into slush to your boot tops, water running on or in the snow pack, roller balls, wet sluffs, ski pole sinks to hand grip, moderate to heavy rain fall, recent wet slides.  Glide avalanches are another type of wet slide and are also more common in Spring.  We see more of these in the Castle Crags Wilderness and Castle Lake area where smooth rock surfaces exist.

The Five Red Flags of Avalanche Danger any time of year include:  1) Recent/current avalanche activity  2) Whumpfing sounds or shooting cracks  3) Recent/current heavy snowfall  4) Strong winds transporting snow  5) Rapid warming or rain on snow. 


2008/2009 Winter Season:  Following a very dry summer, we had significant snowfall above tree line in early November with 5-7 feet.  Warm and dry weather followed, creating a smooth and firm melt/freeze snow pack 2-3 feet deep above 8500 ft. in elevation.  Unusually cold weather in the second week of December created weak layers.  A warm front at the end of December created a rain crust.  Most of January was warm and dry, with moderate winds.  At the end of January our snow pack was 28% of normal.  Wet weather returned and at the end of February, our snow pack was 82% of normal.  At the end of March our snow pack was 85% of normal.  Seasonal precipitation by 4/12/09 was 84% of normal (on that date in 2008 we were about 74%). La Nina conditions were in effect all winter and are forecast to weaken this spring.  Many natural avalanches occurred during and shortly after storms.  Several human triggered avalanches occurred with only minor injuries and no fatalities this season.

Video of Mt. Shasta snowpack 4/5/09 

Go to "Photos/Avy Shots" for photos of recent avalanches.

Go to "Forums", "Snow pack Videos" to see past snow pack videos.

The final avalanche advisory for the season was 4-12-09.  We will be updating the Climbing Advisory page intermittently as conditions change: www.shastaavalanche.org.  We would like to thank you for your interest in this service.  This includes everyone who sent in avalanche and snowpack observations. These observations are a vital part of the daily avalanche hazard assessment and we really appreciate your input. We hope that we have helped in making your backcountry experience safer.  If you have any suggestions or comments please feel free to contact us:  U.S. Forest Service, Mt. Shasta Avalanche Center, 204 W. Alma St.  Mt. Shasta, CA 96067.  We look forward to sharing more avalanche information with you next season.  In the mean time, enjoy your spring and summer, and be safe out there!   

Please report weather and snow observations:  (530)926-9614  Thanks!   Wink



The Five Red Flags of Avalanche Danger any time of year include:  1) Recent/current avalanche activity  2) "Whumpfing" sounds or shooting cracks  3) Recent/current heavy snowfall  4) Strong winds transporting snow 5) Rapid warming or rain on snow.

 

 

 


Ranger Station Info

Avalanche Specialists and
Lead Climbing Rangers:
Eric White & Dan Towner                                                                                        Climbing Rangers: Nick Meyers, Jon Dove & Forrest Coots
For more information call: (530) 926-4511
Winter/Spring Hours: 8:00 AM to 4:30 PM, Monday - Friday.
Summer hours starting May 16th - Open 7 days a week, 8am-4:30pm                                                              Mt. Shasta Avalanche Center and Wilderness Dept.
Mt. Shasta Ranger Station
Shasta-Trinity National Forest
204 West Alma Street
Mount Shasta, CA 96067
Avalanche/Climbing Hotline (530)926-9613

Live Shasta Cam

Mount Shasta Snow Cam courtesy of SnowCrest, Inc.
Courtesy of SnowCrest, Inc.