Rockfall, weather and avalanches, as land managers describe them.

Yosemite: a rockfall record back to 1857

The US Geological Survey (USGS) keeps a database of rockfall in Yosemite National Park. Stock, Collins, Santaniello, Zimmer, Wieczorek and Snyder (USGS Data Series 746, 2013) documented 925 events from 1857 to 2011, and recorded that rockfalls and other slope movements had killed 15 people and injured at least 85 since the first documented fall in 1857. The database records location, date, volume and probable trigger. Yosemite Valley's granite cliffs, nearly a kilometre tall, sit above about 4 million visitors a year.

A later USGS assessment (Stock, Luco, Collins, Harp, Reichenbach and Frankel, 2014) calls rockfalls common in Yosemite Valley and a substantial hazard and risk to visitors. An earlier USGS report (Wieczorek, Morrissey, Iovine and Godt, 1998) says no area of Yosemite Valley has a zero chance of a large rock avalanche, that many small falls probably go unreported, and that most falls are linked to triggers such as earthquakes, rainstorms and rapid snowmelt, though some have no obvious trigger. It put the return period for a fall the size of the 1996 Happy Isles event, about 30,000 cubic metres, at about 11 years.

The casualty counts differ by source. The USGS gives 15 deaths and at least 85 injuries for 1857 to 2011; a local newspaper after the September 2017 El Capitan rockfall gave 16 deaths and more than 100 injuries since 1857 (from a search summary). Later events and different counting probably explain the gap, but the sources do not say.

Grand Teton: snow, rock and lightning

In Accidents in North American Climbing 2016, the American Alpine Club (AAC) published Joel Peach's study of 74 incident reports covering 78 parties on the Grand Teton's Exum Ridge and Owen-Spalding routes from 1950 to 2014, with conclusions reviewed by park rangers. About 85 percent happened in summer and about one in four was fatal. Falls on snow, mostly on descent, were the most frequent contributing factor, and falls on rock about a quarter. Lightning strikes were recorded on the upper mountain, nearly all after noon, and about one incident in ten involved losing the route. Ranger George Montopoli said snow-travel accidents had declined relative to other causes, linking this to less snowfall and faster melting in recent summers.

On 27 August 2013 the park reported that a rockslide in Garnet Canyon had buried a climber, who suffered multiple traumatic injuries. It said afternoon rain after dry weather had created prime conditions for rockfall.

Canada: rockfall, icefall and avalanches

Parks Canada publishes yearly accident reports for its mountain parks as case studies. Its 2014 list for Banff, Yoho and Jasper includes lead falls on ice, a climber struck by falling rock on Wiwaxy Peak, overdue parties and three avalanche incidents. After a rockfall at Bow Glacier Falls in Banff National Park killed two hikers in June 2025, field unit superintendent Francois Masse said the mountains are not a controlled environment and there is always some risk; the trail reopened in July 2026 with warning signs. A geotechnical assessment by Dave Gauthier for Parks Canada said further rockfall from the same face was reasonable to expect, though it was not a formal risk assessment.

Climbing reports describe the same hazards. The Alpine Club of Canada listed overhead hazards, including rockfall from parties above or dislodged rock, as a theme of the 2018 Canadian reports. ANAC 2003's Canadian section linked rockfall and icefall to rapid temperature change. A 2008 study of rescues in Banff, Yoho and Kootenay parks from 2003 to 2006 is reported in a search summary to have found avalanches behind 45 percent of 40 deaths; the full text could not be read, so that figure is unconfirmed.

Avalanches and climbers

The AAC's Prescription (May 2021), citing a national avalanche database, reported that climbers were involved in 39 of 44 June avalanche deaths and 31 of 43 May avalanche deaths in the US since 1951. Caroom's 2020 analysis of ANAC narratives found avalanches in 13 percent of ice climbing accidents and 10 percent of alpine accidents.

In Scotland, the Scottish Avalanche Information Service (SAIS) forecasts for six areas through the winter: Lochaber, Glen Coe, Creag Meagaidh, the Northern and Southern Cairngorms, and Torridon. In April 2023 it had logged 146 avalanches that winter, against 162 the winter before and a record 350 in 2014-15. Its coordinator, Mark Diggins, said conditions change more quickly than before, avalanches come in shorter windows, the snowline is moving higher with climate change, and hazards remain near gully tops and summits even in lean winters. News sources give different season totals for some winters (205 and 237 for 2015-16, from a search summary).

The Alps: thawing ground and bare glaciers

In late July 2026, according to Swiss broadcaster SRF, the Swiss Alpine Club (SAC) said a snow-poor winter, a warm spring and repeated heat waves had made high-alpine conditions harder, that many glaciers were largely bare ice, and that thawing permafrost may raise rockfall risk and destabilise terrain. In 2022 the SAC recorded 70 people falling into crevasses, against a 10-year average of 38, six of them fatally; it attributed this to poorly snow-covered glaciers. In Austria, Rugg and colleagues (2020) found rockfall came before 229 of 894 fall-related injuries in rock climbing emergencies from 2005 to 2018.

A different picture in Scotland

Not every data set puts objective hazards high. Scottish Mountain Rescue's 2024 report recorded rockfall as a factor in only three mountaineering incidents, and most incidents happened in fine weather (142 records). Its population is mostly hillwalkers, not climbers. For how the bodies rank all causes side by side, see what the accident data shows.