Seward & Southern Kenai Mtns

Archives
Issued
Fri, April 19th, 2024 - 7:00AM
Expires
Sat, April 20th, 2024 - 7:00AM
Forecaster
Mik Dalpes
Conditions Summary

Weekend Avalanche Outlook

Saturday, April 20 – Sunday, April 21

Bottom Line: Spring transition is in full effect and this weekend we could see both wet and dry snow problems. Warm temperatures all weekend and sun on Saturday will make wet loose avalanches likely to occur on steep east, south, and west facing slopes. Roller balls are an indication to start looking for a colder aspect. Strong winds occurring on Friday and Saturday will make wind slab avalanches a concern on colder slopes. Watch for blowing snow and avoid those places where it is landing.

Special Announcements

Avalanche Center End of Season Operations: Today, April 19 will be the last “Weekend Avalanche Outlook” for the season. Next week we will post some “spring tips” which will be our last post before the first product next season.

Recent Avalanches

Recent Avalanches: On Wednesday, April 17 I observed a large pile of wet debris on a south aspect of Mt. Alice at about 3,500′ that looks like it was triggered by a cornice fall. A slab that is likely due to wind was observed today, April 19 on the east face of Mt. Marathon. It initiated near the ridge of Race Point and looks shallow but propagated wide. One glide avalanche was also observed today on a northwest facing slope on the east side of Resurrection Bay.

Weather Recap: It was a breezy week in the Seward area with winds averaging just above 10 mph for four out of the last seven days gusting in the teens to upper 20s mph. The wind was out of the north early in the week and switched to the south later in the week with a weak front passing through. Grouse Creek weather station at Mile 12 recorded 0.5″ snow water equivalent (SWE) and 2″ of new snow this week. Temperatures warmed up averaging in the 40s most days at 1,200′ (Cooper Lake weather station). The snow was freezing hard at night through the 15th, but temperatures have been above freezing since then at 1,200′. As of Friday afternoon April 19, ridgetop winds are blowing strong from the east.

Weather Forecast: Saturday should feel like spring although the wind could be blowing hard. Partly sunny skies are forecast along with temperatures in the mid 40s F during the day both at Lost Lake and in the town of Seward. Ridgetop winds are forecast to blow 30 to 35 mph from the southeast gusting into the 40s mph. Winds should calm to 10 to 20 mph and clouds look to move in Saturday night. Temperatures at Lost Lake are forecast to reach 40 F during the day and rain line could be as high as 2,000′ with 1 to 3″ of new snow accumulating by Sunday evening as a weak front passes through. Nighttime temperatures look to stay above freezing up to 2,000′ Friday through Sunday at 34 to 36 F depending on elevation.

Fresh glide avalanche on a northwest facing slope on the east side of Resurrection Bay. 04.19.2024

Avalanche Problem 1
  • Wet Loose
    Wet Loose
Wet Loose
Wet Loose avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
More info at Avalanche.org

With temperatures forecast in the mid 40s F and the sun shining between some clouds, wet loose avalanches are the main concern on Saturday. The wind on Saturday is forecast to be blowing in the 30s mph which will help to keep the surface cooler than it would be otherwise, which may limit the size and likelihood of loose wet avalanches.

Watch for roller balls as an indication that the snow is warming, and natural wet loose avalanches are likely to occur. Wet loose avalanches are especially likely to be triggered in the lower elevations near rocks and vegetation which are attracting heat. These avalanches will likely be small at upper elevations but could grow larger in size as they reach lower elevations where there might be less wind and higher temperatures are warming the snow deeper into the snowpack. One good test for this type of problem is to step off your machine, board, or ski and see how far your boot penetrates into the snow. If you sink to your ankle in wet looking snow it’s time to look for a colder aspect. Sunday looks cloudy so it will be less likely that wet loose will be as big of a problem.

Glide Avalanches:  We’ve noticed glide activity starting to return to the area, with many glide cracks opening up throughout the entire CNFAC forecast area and a handful of cracks releasing as glide avalanches. With continued warm temperatures on the way, we are expecting to see glide activity continue. These avalanches are large and unpredictable, so it is important to avoid spending any time under open glide cracks.

Wet Slab: With temperatures as warm as the mid 40s F and no freeze for 3 nights in a row there is a chance a larger wet slab avalanche could occur. This is most likely to occur in lower elevations and could be triggered by a wet loose avalanche. These avalanches are large and dangerous because they are made of heavy wet snow which is difficult to escape. We recommend using the tips in the above paragraph to avoid snow that is approaching wet slab potential.

Cornice fall: With a recent large cornice fall observed in the Seward area we can expect there will be more, especially with the forecast for sun and warm temperatures this weekend. We recommend limiting time underneath cornices and give them a wide margin if you are traveling above them as they can break back further than expected.

Wet loose avalanches on a northwest facing slope on the east side of Resurrection Bay. 04.19.2024

Wet loose avalanches on a southeast facing slope in the Lost Lake area. 04.16.2024

Avalanche Problem 2
  • Wind Slabs
    Wind Slabs
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
More info at Avalanche.org

As of Friday afternoon April 19, strong easterly winds are blowing off the ridgelines in the town of Seward. Tomorrow, southeast winds are forecast to blow in the 30s mph gusting into the 40s mph. With these conditions and forecast we expect small wind slabs up to 1′ deep to be developing above treeline. Unlike last week, there is a crust or a few inches of wet snow on all aspects except north so there is not as much snow available to be moved around by the wind this weekend. If the forecast verifies, the winds will be so strong that some of the snow will blow away or sublimate while some of it will land below ridgelines or across gully features. As usual, we recommend watching for recent avalanches and blowing snow and avoiding the places where it’s landing.

Travel tests work well for this type of problem which include feeling for stiff snow over softer snow, digging a quick hand pit, or riding or jumping on a small test slope to see how the wind deposited snow is bonding to the snow beneath. A whumpf or a shooting crack are clear signs the snowpack needs some time to adjust.

Weather
Fri, April 19th, 2024

Weather Forecast Links:

NWS Point Forecast: Point forecast near Lost Lake.

NWS Avalanche Weather Guidance (AVG) forecast page: Zoom into the Anchorage bowl for special detailed winter forecast.

Windy.com Spot Forecast: Spot forecast for Lost Lake. (tip: scroll through models using the links at the bottom of the page, and change locations by clicking on the map).

Weather Stations

Grouse Creek Divide Snotel

Lost Lake Weather Station

Observations
Recent Observations for Seward & Southern Kenai Mtns
Date Region Location
04/16/24 Seward Observation: Lost Lake
04/10/24 Seward Observation: Lost Lake
04/03/24 Seward Observation: Snug Harbor
03/31/24 Seward Avalanche: Lost Lake
03/27/24 Seward Avalanche: Tiehacker Mountain
03/14/24 Seward Observation: Lost Lake via Snug Harbor
03/06/24 Seward Observation: Carter Lake
03/03/24 Seward Observation: Victor Creek, 1k – 1.6k elevation
02/29/24 Seward Observation: Carter Lake
02/26/24 Seward Avalanche: Mt Marathon
Riding Areas

The riding areas page has moved. Please click here & update your bookmarks.


This is a general backcountry conditions summary. This advisory does not apply to highways, railroads or operating ski areas.