Near Miss: Girdwood

Raggedtop, Crow Creek – Near Miss Report
Chugach Mountains, Alaska

Location: Northeast facing bowl on the east shoulder of Raggedtop Mountain
Lat/Lon: 61.009309 N, -149.117572 W
Date: January 25, 2025, time: 8:45pm
Report by: Chugach National Forest Avalanche Center (CNFAC)
Contact: staff@chugachavalanche.org, website: ChugachAvalanche.org

Avalanche Summary

This avalanche occurred naturally on the third day of a warm, wet, and windy storm. The crown was unusually well connected and debris ran 2750′ in vertical distance and 5660′ (1.1 mi) in horizontal distance to an alpha angle of 26 degrees. No one was injured, but the size of the avalanche and the proximity to inhabited structures was alarming. This report is focused on compiling available information about this event as well as some historic events in this avalanche path.

Avalanche Information

Type: Unknown
Problem/Character: Storm Slab
Crown Depth: 3-4′
Width: 3,000’
Vertical Run: 2,750’
Trigger: Natural
Aspect: North – East – Southeast (wrapping around majority of bowl)
Elevation: 4000′ at crown, 1250′ at debris terminus
Slope Angle: 35 to 40 degrees
Slope Characteristics: Large bowl with steep rocky terrain at upper elevations and well connected planer slopes below, runout down a long path over several low angle steps into alder and stands of mature hemlock at lower elevations.
Code: SS-N-R4-D4-U

Backcountry Avalanche Forecast

The CNFAC rated the avalanche danger at HIGH at all elevations and issued a backcountry avalanche warning through the National Weather Service valid from Saturday January 25th at 7 am through Sunday January 27th at 6 pm. The forecast described the conditions as “An intense storm is bringing heavy precipitation with very strong winds, making very large natural avalanches very likely. These may run long distances into flat, low-elevation terrain below steeper slopes. Avalanche conditions are very dangerous, and traveling in and below avalanche terrain is not recommended.” This forecast product is written for public backcountry recreationists, and is not intended for urban infrastructure. The Crow Creek area falls within the northwest corner of the CNFAC Turnagain Pass forecast area.

Weather and Snowpack Summary

A major storm impacted Southcentral Alaska Jan. 24 to 26, bringing 6″ of SWE and 4 to 5 ft of dense snow to Girdwood. Raggedtop lies on the northern side of the Girdwood Valley, which is typically drier and may have received less snow compared to the weather station reports from Alyeska Resort on the southern side of the valley. The preexisting snowpack on Raggedtop is largely unknown because low snow cover limited backcountry access in the early part of the season. Based on limited field observations prior to the avalanche, the snowpack in the Crow Creek area of Girdwood was thinner than normal and harboring weak layers of facets. We do not have enough information to determine if the avalanche released at the interface with the old snow or on a buried weak layer. There were widespread large natural avalanches in the Crow Creek area during this storm cycle.

For the Turnagain Pass area in general, the CNFAC had been monitoring a layer of weak snow that was buried during a major storm event in the first week of January. With an exceptionally wet January, the layer had been buried by 16.8″ Snow Water Equivalent (SWE) at the Center Ridge Snotel site during the weeks leading up to the event. This weather station is situated roughly 15 miles south of Crow Creek neighborhood at 1800′ elevation at Turnagain Pass. The layer had not produced any major avalanche activity in the Turnagain Pass zone despite multiple storm systems contributing 2-3″ SWE over 48 hours or less, and as a result the CNFAC had dropped the layer as a concern for Turnagain Pass. There were no other known problems within the snowpack.

Accident Summary

Luckily, there was no one injured in this avalanche and as far as we know no structures were seriously damaged. One vehicle was damaged and the debris ran over the top of a structure that was built into the side of the hill.

History of Avalanche Path

This report will act as a living document to catalog avalanche activity in the Raggedtop avalanche path. As more information becomes available, such as photos or historic accounts from locals, we will add it to this report to help document the local avalanche history.

Due to the magnitude of this avalanche event, we collected tree ring samples from a stand of mature hemlocks that were wiped out by the debris. We aged the three trees at roughly 66 years, 102 years, and 107 years. These ages indicate that avalanches of this size are relatively rare in this portion of the avalanche path. Some of the tree ring samples showed evidence of being impacted by prior avalanche events. Relative to the size of this avalanche path this event only encompassed a small portion of the potential runout zone. Much larger events are possible in this avalanche path based on the forest trim lines.

The Municipality of Anchorage conducted avalanche hazard zoning in 1982 which deemed the Raggedtop avalanche path that impacts the Crow Creek neighborhood as a ‘high hazard’ zone with an approximately 10 year return frequency. (See links for detailed hazard zoning report and interactive web map). Based on discussions with locals who have lived in the Crow Creek neighborhood for many decades, the last avalanche event to run this far made it to the main road in the late 1990s.

Thank you to everyone who helped compile this report.