WORDS: Brian Irwin
On Saturday, March 29, a large avalanche swept the southeast section of New Hampshire's Mount Washington's summit cone. According to U.S.F.S. Snow Ranger Chris Joosen, "A slide of this magnitude has never been recorded on this particular slope." Suspected to be skier triggered, this aspect of 6,288-foot Mount Washington rarely avalanches and is a moderate slope popular for backcountry skiers. Roughly 20 individuals were on the slope when the avalanche occurred at approximately 1 p.m. No one was caught in the slide.
Mount Washington is perhaps best known for its venerable Tuckerman Ravine, an area that draws thousands of visitors on spring weekends. The U.S.F.S. Mount Washington Avalanche Center forecasts this area, but not the summit cone, an area that is largely considered less prone to avalanches than the steep gullies of Tuckerman and neighboring Huntington Ravine.
Joosen estimates the slide meets criteria for a D3 avalanche, which means it has the potential to destroy a wood-frame house. Field analysis revealed the crown face was three feet deep and 650 feet across. The avalanche ran 385 vertical feet. It was thought to have occurred when a weak layer of facets beneath an ice lens collapsed, allowing the overlaying hard slab to run.
The slide was first reported by Harvard Cabin caretaker Rich Palatino. U.S.F.S. Snow Rangers responded immediately. After a three-hour avalanche dog and beacon search, extensive interview of witnesses, and evaluation of the pile, which was 20 feet deep in places, it was determined that there were no casualties.
Avalanches are not uncommon on Mount Washington and in New Hampshire's Presidential Range. However, in that region, larger slab avalanches most frequently occur during or after a storm. On the day of the incident, skies were fair and avalanche conditions in Tuckerman were rated at moderate, "with the primary concern being wet slabs." Joosen explained that this slide was unique in that "warm weather and free water did not appear to be a causative factor in triggering this event."
Mount Washington is situated only three hours from Boston and is frequented by experienced and inexperienced backcountry enthusiasts alike. Despite the fact that the summit cone is not forecasted, this event is a powerful reminder of the need to be vigilant when using the backcountry.
Be sure to read your local avalanche report from an avalanche center near you.