Haines Avalanche Center

Forecast Expired - 03/19/2023

Above 2,500ftConsiderable

1,500 to 2,500ftConsiderable

Below 1,500ftConsiderable

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Storm Snow:

The Bottom Line: Expect avalanche sensitivity to increase as temperatures rise and the sun comes out to produce strong solar radiation. This zone received up to 4 feet of new snowfall or more in the last 3 days, strong southeast winds and a temperature increase of nearly 20 degrees F. That is a HUGE new load and stress that still needs time to bond to a variety of old snow surfaces. Consider the upside-down new snow extremely suspect on slopes greater than 30 degrees and avoid terrain traps (steep openings and gullies) along with run-out zones, like the plague.

 

Loose surface snow can entrain mass quickly as it moves down slope, be vigilant at and below treeline where warm temperatures have saturated upper layers of the snowpack (see Wet Avalanche problem below). Above treeline recently formed cornices and thick dense wind slabs are mega suspect on leeward slopes (W-NW-N-NE) and should be avoided.

 

The old snow surfaces (bed surface) for new snow to run over include: rough, smooth, ice, melt-freeze crusts, sun crusts, sastrugi, wind slab and 4-8″ of diural facets, or weak sugar snow. A prior knowledge of where/how these surfaces formed are highly dependent on aspect and elevation.

 

Any surface avalanches within the new snow could step down to one or more Deep Persistent weak layers and cause a very wide and deadly avalanche. Consequences remain high. Give runout zones a wide berth. Human triggered avalanches are likely and natural avalanches are still possible.

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Wet Avalanches:

Snow levels reached up to 2500′ over the last 24 hours. Below that level, especially less than 1500′ there was a lot of rain-on-snow. Wet slabs and large wet-loose avalanches are likely today below 2000ft, especially in open terrain steeper than 32 degrees.

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 3

Deep Slab:

Recent heavy snowfall and strong warming is stressing the remaining persistent weak layers deeper down in the snowpack. The result is an increased likelihood of very large and deadly avalanches that can break super wide across a slope.

 

When seeking out wind protected zones, remember that wind-protected pockets may be harboring buried surface hoar layers. Protected means preserved. 

 

Buried surface hoar from Feb 4 is sitting over the Jan 25th melt freeze crust, about ~4-5′ deep. There are also small-grained facets on this crust. These layers have become less reactive in snowpits, but smaller slides could still step down and trigger them.

 

Snow pit from Feb 22 in Lutak (NE aspect 1800ft) showing persistent weak layers below the snowfall from Feb 10-15.

 

An unlikely to trigger, but high consequence deep slab layer remains. The “Big Warm-Up layer” from Nov 17th is not to be forgotten about. Although currently dormant, a smaller slide triggered on the upper snowpack could step down and trigger this deadly beast near the ground.

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

March 16: Multiple D2 crowns in cross-loaded gullies 1-meter deep on SW-aspect near 3000ft observed in Lutak Zone.

March 7-9: Multiple D2 natural wind slab avalanches in top 45cm, on wind loaded SW, S, SE aspects in the Transitional zone, 3000-4000ft.

March 4-5: Human triggered wind slab D1/D2 at 5-mile creek Chilkat Pass, 2200ft, W aspect

D2-R4 hard slab: Mid-slope propagation, E aspect, in steep wind loaded area, unsupported slope.

D2-R4 New Faithful, W aspect, high alpine

March 2: Small natural soft slabs were observed in steep trees in the Lutak zone. This kind of small to large natural activity is likely widespread in the Lutak zone.

Feb 19-23: 6 different observations of natural avalanches in the transitional zone and in the Chilkat range. The natural D2 slides were on all aspects, a few on lower angle, all running on a mid-snow pack layer, and a majority with widespread propagation.

A larger, D3-R4 natural avalanche was observed near Four Winds on a S, SW aspect, down 60-120cm, it looked like a loose wet slide that maybe stepped down to a lower layer. Widespread propagation.

Feb 9: Glide cracks ~3000-3400′ in the transitional zone on N, NE aspects. Also notable was observation of reloading of bed surfaces on previous slides.

Jan 28: Two D2’s in the Glory Hole. NW-aspect around 3,200′

Jan 25-29th Multiple wide propagating natural slides released.

 

 

Weather

Forecast:

Saturday should begin to clear out as winds and precipitation begin to tapper by morning. Freezing levels are expected around 1500ft with a peak warming trend later in the day and variable light winds. An active pattern returns into Sunday as the chance for precipitation increases.

 

Recent Weather Summary:

  • March 15-16: 2-4 feet of new snow, strong south winds, and warming temperatures, snow levels reached about 2000ft.
  • March 4-7 strong NW / N outflow event with cooling temps.
  • March 1st brought a strong and cold storm, with 10-15″ of new snow inland, and 30″+ in the Lutak zone.
  • Late Feb 20-Feb 23 a cold high pressure system with moderate to strong N, NW winds
  • Feb 19-Feb 20- warmer, solar effect on south aspects, valley fog on the 19th at ~1500-2000 ft.
  • Feb 12 freezing levels 1250ft
  • Incremental snow (more in Lutak zone) since Feb 5th, periods of moderate S/SE winds
  • Feb 1-4 Near surface facets on top of crust from Jan 25 warm-up
  • Jan 17-26 brought around 5″ of precip (3-5feet of new snow above 3000ft), strong SE winds, and a noticeable warmup
  • Surface Hoar and Near Surface Facet growth Jan 8-10
  • A strong front brought 24-30″ of snow above 2000ft on Jan 2nd.
  • There was widespread Surface Hoar growth on Dec 31st.
  • Complete Season Histories:     Transitional Zone     Lutak Zone

 

 Snow Depth Last 24-hr Snow/SWE Last 3-days Snow/SWE  Today’s Freezing Level   Today’s Winds Next 24-hr Snow/SWE
Mount Ripinsky @ 2,500′  158″   2″ / 0.10″  42″ / 3.50″  1500′ light, variable   2″ / 0.10″
Flower Mountain @ 2,500′  83″   2″ / 0.10″   26″ / 2.20″  1500′ light, variable   2″ / 0.10″
Chilkat Pass @ 3,100ft  54″   1″ / 0.05″   19″ / 1.55″  1500′ light, variable   1″ / 0.05″

 

Additional Information

WEAR A HELMET! Be careful of rocks and hidden hazards. Be prepared for crevasses when on a glacier. 

Are your riding companions trained and practiced in avalanche rescue? Everyone in your group needs to have a beacon, shovel, and probe, and know how to use them. Our mountains have very limited cell coverage, carry an emergency communication device and enough gear to spend the night.

Avalanche Canada’s Daily Process Flow – Utilize this every day you go out in the mountains.

Announcements

Click the +Full Forecast link below for each zone to read more.  If you see any recent natural avalanche activity, or signs of instability please submit an observation.