CNFAIC Avalanche Advisory (Turnagain Pass Area)

Friday, February 3rd 2012 Current Advisory (Turnagain Area)

Kevin Wright — 2012-02-03T20:09:00+01:00

Danger Rating: Considerable
Trend: Increasing Danger

Good morning. This is Kevin Wright with the Chugach National Forest Avalanche Information Center on Friday, February 3rd at 10am. This will serve as a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

ANNOUNCEMENT
Seward Highway DOT will be doing more avalanche reduction work today. Expect intermittent road closures between Summit lake and Seward. Check the 511 hotline or http://511.alaska.gov/ for the latest information. As of yesterday evening there were no parking areas plowed in Turnagain Pass. Be patient with the plowing efforts and do not block the road crews.

BOTTOM LINE
Avalanche danger is at CONSIDERABLE this morning for much of the region. The current storm system is producing heavy snowfall in Girdwood and Turnagain Arm. Pockets of HIGH danger are building again. Human triggered avalanches are likely on steep and/or wind loaded slopes. Natural avalanches are possible. Expert level avalanche avoidance skills are important for anyone traveling in the backcountry today. Many areas of the backcountry should be avoided completely today.

AVALANCHE DISCUSSION
A late morning update in the weather forecast has greater snowfall amounts accumulating in the region. All this snow is adding significant weight to an already overloaded pack. Conditions are changing fast, and avalanche danger is back on an increasing trend.

The majority of the snowfall from this storm is still recent enough to justify a Considerable danger rating. The peak storm intensity, with wind up to 120+ at ridgetops and most of the 2+ feet of snowfall occurred on Wednesday. Yesterday added another 4-8 inches in some areas, and a foot or more could fall today. This is a lot of extra weight on the snowpack in a short period of time. Steep slopes are ripe for a human trigger today, and natural avalanches are still possible.

Avalanche workers were finding a reactive snowpack at mid and high elevations yesterday. We found easy to moderate and clean shears within the storm snow in several different layers. One large natural avalanche crossed the Seward Highway at mile 37 yesterday morning, shutting down the road just North of the Sterling Y.

MOUNTAIN WEATHER
It is currently snowing hard in Girdwood and Turnagain Arm. Wind remains light at the ridgetops, but snow accumulation at all elevations is quickly becoming significant.

The last 2 days has brought an intense storm to the region. On Wednesday 2-3 feet of snow fell above 1000 feet in Girdwood, Turnagain Pass, and parts of the Kenai. Summit Lake got 14 inches of slightly drier snow. Thursday had intermittent snowfall with another 4-8 inches in some areas. This storm came in a little warmer, so sea level elevations got rain that transitioned to snow a few hundred feet up.

The majority of the major storm has passed our region, but another wave is entering Prince William Sound this morning. 8-14 inches of additional snow is possible today, with moderate wind and slightly lower temperatures in the mid 20s.

CNFAIC Weather Page and the NWS forecast

I will issue the next advisory Saturday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.

Thursday, February 2nd 2012 Current Advisory (Turnagain Area)

Wendy Wagner — 2012-02-02T17:16:00+01:00

Danger Rating: Considerable
Trend: Decreasing Danger

Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Thursday, February 2nd at 7am. This will serve as a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

ANNOUNCEMENT
Alaska DOT crews will be conducting avalanche hazard reduction along the Seward Highway today. Expect intermittent road closures between 10am and 3pm. Visit http: http://511.alaska.gov/ for updated information.

BOTTOM LINE
Pockets of HIGH avalanche danger remain in areas where strong winds and continued snowfall and/or rain persist in the wake of yesterday's intense storm. In most areas this morning, winds and snowfall rates are tapering off and the danger is CONSIDERABLE. Though the storm, and avalanche danger, is decreasing, dangerous avalanche conditions still exist. Human triggered avalanches are likely on ALL SLOPES at ALL ELEVATIONS today and expert level route finding skills are required for safe backcountry travel.

AVALANCHE DISCUSSION
Heavy snowfall, rain and hurricane force winds pounded our region yesterday. The avalanche danger was updated to HIGH as the storm intensified mid-day. Natural avalanches occurred and, though driving conditions and visibility were very poor, debris piles were seen at the bottom of some avalanche paths. One of three paths at mile 106 on the Seward Highway slide and deposited snow on the road.

Storm snow instabilities are the primary concern today with continued moderate snowfall and strong ridgetop winds. These will be in the form of: Wind slabs, soft slabs and loose snow avalanches. Soft slabs were exceedingly touchy yesterday on slopes over 35 degrees in the relatively 'safe' treed locations. We were able to trigger these 10-16" slabs at will on steep rollovers. This is indicative of how the snow is reacting and bonding to the old surface. Though this weakness has likely settled out to some degree today, new snow and continued wind will keep the hazard up.

Lower elevation slopes (below 1000'):
Wet avalanches are also a concern where rain has fallen on snow. Very heavy and wet snow exists at these elevations and, until cooler temperatures lock it in place, wet avalanches will be possible.

Safer places to recreate are in the flats, or on slopes less than 35 degrees, that are NOT below or connected to steeper slopes and avalanche paths.

MOUNTAIN WEATHER
Heavy snow and rain fell in force yesterday. Some areas saw over 3" of snow per hour at times.
Totals from the mid elevations:
Turnagain Pass: 24-30" snow, ~2" water
Girdwood Valley: 28-36" snow, 2.5-3" water
Summit Late: 14" snow, ~1" water

Winds were off the charts as well. Not only did Sunburst's wind sensor make it through 5 hours of over 100mph gusts intact, it recorded its new record gust - 126mph. Winds were southeast, sustained between 50-85mph. Needless to say, it was bona fide storm day.

Today, remnants of the storm still hang over us and we can expect moderate snowfall (around 6-10" accumulating today) and moderate to strong ridgetop wind (southeast 30mph with 55mph gusts). The snow/rain line is currently right around sea level where temperatures are in the mid 30's. Temperatures will be in the upper to mid 20's F above 1000' and should cool off tonight and into tomorrow.

CNFAIC Weather Page and the NWS forecast

Kevin will issue the next advisory Friday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.

Wednesday, February 1st 2012 Current Advisory (Turnagain Area)

Kevin Wright — 2012-02-01T22:49:00+01:00

Danger Rating: High
Trend: Steady Danger

Good morning. This is Kevin Wright with the Chugach National Forest Avalanche Information Center on Wednesday, February 1st at 7am. This will serve as a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

Afternoon update

BOTTOM LINE
Avalanche danger is rising towards HIGH. Dangerous conditions can be found in the backcountry. Expert level travel skills are essential today to stay in safe zones. Wind up to 120mph and heavy snowfall are quickly increasing the danger in most of our forecast zone.

AVALANCHE DISCUSSION
Somebody must have pushed the reset button� We are just starting to see the effects of a major storm this morning that will build in intensity through the day. Heavy snow and high wind is expected for most of today and tomorrow. The avalanche danger will rise in relation to the amount of new snow and wind.

We know for sure that avalanche danger will increase with storm snow and wind slabs. We don�t have a great idea how easily it will bond to the old snow surface. This is one of the questions we will be trying to answer over the next few days. The new/old snow interface will be the layer of primary concern until we have better information. The good news is we don�t have any truly concerning deeper weak layers. There are some anomalies in specific areas including the buried surface hoar and near surface facets from mid January that formed before the last big storm. The most important information today is that we are getting lots of new snow and overall stability will be poor due to rapid loading.

I expect blowing snow and poor visibility will be enough to signal that traveling above treeline could be dangerous. As the new snow builds, traveling underneath larger avalanche paths will also become dangerous. Lower elevation areas including steep rollovers and wind loaded pockets may become deep enough to have avalanche issues as well. Choosing safe areas will require a high level of skill and experience today.

MOUNTAIN WEATHER
A large storm system is just starting to enter our region this morning. This storm will bring heavy snow and high wind to Prince William Sound, the Kenai Peninsula, and Turnagain Arm. A blizzard warning is in effect from 9am to 6pm today. Snowfall predictions range from 8-24 inches, with East wind up to 89mph at ridgetops. Temperatures should stay just below freezing today, and perhaps warm up a little more tomorrow.

Satellite image from 6am on Feb 1st.

CNFAIC Weather Page and the NWS forecast

Wendy will issue the next advisory Thursday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.

Tuesday, January 31st 2012 Current Advisory (Turnagain Area)

Graham Predeger — 2012-01-31T17:09:00+01:00

Danger Rating: Low
Trend: Steady Danger

Good morning. This is Graham Predeger with the Chugach National Forest Avalanche Information Center on Tuesday, January 31st at 7am. This will serve as a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

BOTTOM LINE
Backcountry travelers will find generally safe avalanche conditions within the advisory area today. There is however pockets of MODERATE danger near ridges and other wind affected areas where shallow wind slabs may lurk. Otherwise, the danger is LOW for the core advisory area.

AVALANCHE DISCUSSION
The better than average skiing and sledding conditions continued yesterday in the Turnagain Pass area thanks to the abundance of snow and cold temperatures over the last 10 days. Surface conditions are smooth and consistent from ridge top to valley bottom. Settlement cones observed yesterday below tree line are well developed and provide visual evidence of the slow deformation and densification of our upper snowpack. This is a sign that this upper layer (the latest storm) of our snowpack is gaining strength.

Our observations yesterday on Sunburst yielded no signs of the recent surface hoar from this weekend. This is good news for this specific area, but this particular observation may not be representative of the entire forecast area. With light snow falling yesterday and last night, it is possible that any lingering surface hoar was covered up intact. We'll be further investigating this today and appreciate any other observations from people out skiing or sled-necking today.

Pockets of moderate danger do still exist for soft, shallow wind slabs. The most likely spot to find these will be near or just below ridges and any cross-loaded slopes such as steep gullies or spines. One can identify these wind slabs by feel. Surface conditions will change from loose, unconsolidated snow to a stronger dense surface layer (wind slab) over a matter of feet.

Our sluffing problem is showing signs of slowing down yesterday as warmer temperatures set in. Loose snow avalanches are still a concern though and can pose a problem for those traveling through steep, extreme terrain. As always, practice safe travel protocol riding slopes one at a time, utilize escape routes/ safe zones and you're bound to have a great day in the backcountry today!

MOUNTAIN WEATHER
Yesterday ushered in light snowfall and the beginning of a significant warming trend that looks to persist through the week. Today appears to be a relatively quiet day as far as weather is concerned. We can expect temperatures to be in the high teens to low 20�s and wind speeds at ridge tops to max out in the 15-20 mph range. A weak surface low dominates the advisory area, keeping us under mostly cloudy skies where we may be able to eek out a trace of snow today.

Things appear to be picking up late tonight and into tomorrow with a large, intense storm developing in the central north Pacific Ocean. A Blizzard watch has been issued for Portage Valley and eastern Turnagain Arm on Wednesday. 5-10� of snow is expected along with strong easterly winds peaking tomorrow afternoon. Temperatures will continue to climb as this storm progresses and we may see above freezing temperatures at lower elevations on Thursday.

CNFAIC Weather Page and the NWS forecast

Kevin will issue the next advisory Wednesday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.

Sunday, January 29th 2012 Current Advisory (Turnagain Area)

Kevin Wright — 2012-01-29T17:03:00+01:00

Danger Rating: Low
Trend: Steady Danger

Good morning. This is Kevin Wright with the Chugach National Forest Avalanche Information Center on Sunday, January 29th at 7am. This will serve as a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

BOTTOM LINE
The avalanche danger is MODERATE in specific wind loaded pockets in steep terrain. We saw one example on Friday of a significant avalanche in a cross loaded South facing gully. Much of the region where most people are skiing, on terrain up to about 38 degrees, has a LOW avalanche danger.

AVALANCHE DISCUSSION
No major news yesterday is keeping the status quo in the backcountry again today. Saturday was a busy day in Turnagain Pass, with skiers and riders stepping it up a notch in terrain. Sluffing looks to be manageable, although still a factor in steep terrain. Pockets of wind slab are found in the usual areas - near ridgetops and rollovers. We neither saw nor heard of any significant avalanche yesterday like the one from Friday.

Primary Concern � Wind loaded pockets in steep terrain.
Larger pockets that might have the ability to propagate into a larger avalanche seem to be rare, but not unheard of. The wind event on Thursday, with ridgetop gusts to about 35mph, formed some slabs of stiffer and cohesive snow. This picture is what we are most concerned about today. Read a description of that avalanche here. The possibility of finding a pocket like this is diminished compared to Friday when that avalanche happened. Despite the infrequent nature of this problem, it�s worth staying vigilant in case you come across something similar. Watch for stiffer snow in areas steeper than 38 degrees.

Secondary Concern � Loose snow sluffing and smaller wind slabs.
This is only a hazard to people in steep and high consequence terrain. We have found the sluffing to be generally manageable and predictable. Small wind slabs are somewhat less predictable than the sluffing, and the manageable nature depends completely on the terrain exposure below. Watch for these areas of stiff surface snow in the top 4-6 inches. You�ll know it when you feel it.

New surface hoar formed over the last 2 days all the way to some ridges. This is not a problem now, but could be when it gets buried by the next storm. Stay tuned for further developments�

MOUNTAIN WEATHER
A temperature inversion remains in place over most of the region. Skiers and riders yesterday who toughed out the cold at the parking lot and pushed up to sunny ridges were rewarded with comfortable calm conditions up high. Valley bottoms are still negative temps this morning, with positive single digits higher up. Wind is predicted to remain minor again today with mostly cloudy skies.
There is a chance of snow tonight, with increasing possibilities over the next couple days.

CNFAIC Weather Page and the NWS forecast

Wendy will issue the next advisory Monday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.