In partnership with: Utah Division of State
Parks and Recreation, The Friends of the Utah Avalanche Center, Utah Department
of Emergency Services and Homeland Security and
“keeping
you on top”
AVALANCHE ADVISORY
Saturday,
December 16, 2006 7:30 am
Good morning, this is Evelyn Lees with
the
Current Conditions:
Thankfully, a nice
shot of snow is starting to cover up some of the worst riding conditions of the
year. As of 6 am, snow totals are 5 to
8” south of I-80, and 2 to 6” to the north.
It’s light, fluffy powder, averaging less than 6% density. The northwesterly winds dropped off before it
started snowing, and are less than 10 mph along most ridges, with 15 mph
averages across the highest peaks.
Temperatures also plummeted last night, and are in the teens and single
digits. Turning and riding conditions
will be dust on crust, with lower angle slopes and slopes with a smooth old
snow surface offering the most consistent turns.
Snowpack and Avalanche Conditions:
On Thursday and
Friday, avalanche activity was focused in the Ogden and Logan area mountains, which received the most snow and had a
preexisting shallow weak snowpack.
Activity continued in the
Today, I expect new
snow avalanches in the form of loose snow sluffs and a few very soft
slabs. Because temperatures cooled
before the snow arrived, the new snow landed on hard,
frozen crusts on most aspects and elevations. Any sluff or soft slab you
trigger may run faster and farther than expected on slopes with slick crusts
beneath. Also, yesterday’s stronger
winds did form a few drifts along the upper ridgelines that are now hidden, but
could break out wider than expected and surprise you. Heavier snowfall and slightly stronger winds
are forecast for late this afternoon and tonight. If you are anywhere the winds start to drift
the snow or the snowfall rates increase to more than an inch/hour, the
avalanche danger will increase, and it’s time to become more conservative,
particularly avoiding any fresh drifts of wind blown snow.
Looking into the
future, we are still very concerned about the snowpack above about 9,000’ with
its various layers of weak sugary facets, especially in shallow snowpack
areas. As you travel today, continue to
do lots of pole handle plants to gauge the depth and weakness of the pack. Quick hand pits are an excellent way to check
for the bonding both above and below the crusts. The crusts are thinnest at the higher
elevations, with a variety of facets beneath, so these slopes will have the
first potential for slides to break into old snow. The facets at the low to mid elevations below
about 8,500' should freeze up solidly. Check out 3
new snowpits by our observers.
Bottom Line for the
The avalanche danger
is MODERATE on slopes steeper than about 35
degrees, especially along upper elevation ridgelines. Human triggered avalanches are possible, and
particularly avoid any slope with drifts of wind blown snow. Below about 8,500’, the avalanche danger is
generally LOW. With
more snow and wind in the forecast, it will be a weekend of rising avalanche
danger.
Mountain Weather:
A cold Pacific storm
system will produce snow, heavy at time, through Sunday, with the heaviest
snowfall anticipated Saturday night.
Today, expect periods of snow, with an additional 6 to 9” possible south
of I-80, and 3 to 6” to the north. Winds
should remain light today and tonight, generally less than 20 mph, from the
northwest and north. Temperatures will
be near 10 at 10,000’ and in the low 20’s at 8,000’. Snow will continue tonight and Sunday, with 5
to 12” possible, again with the heaviest amounts south of I-80. Temperatures will be in the single digits and
low teens tonight.
Announcements:
Wasatch Powderbird Guides ski season has started, but they will not fly
today due to weather and snow conditions.
Listen to the
advisory. Try our new streaming audio or
podcasts
Our new,
state wide tollfree hotline is 1-888-999-4019.
(For early morning detailed avalanche activity report hit option 8)
For a list of avalanche
classes, click HERE
For our classic text
advisory click HERE.
To sign up
for automated e-mails of our graphical advisory click HERE
We appreciate any
snowpack and avalanche observations you have, so please leave us a message at
(801) 524-5304 or 1-800-662-4140, or email us at [email protected]. (Fax 801-524-6301)
The information in this
advisory is from the U.S. Forest Service, which is solely responsible for its
content. This advisory describes general
avalanche conditions and local variations always occur.
Drew Hardesty will
update this advisory by 7:30 on Sunday morning.