Alaska landslides and avalanches

Every recorded landslide or avalanche record since 1996 · 19 counties with a record

NOAA's Storm Events Database records 102 landslide and avalanche records in Alaska from 1996 through June 30, 2026, about 4.0 a year since 2000. The deadliest was the November 20, 2023 debris flow: 6 deaths, 1 injury and $2.1 million in damage in 2025 dollars across 2 records. Alaska ranks 7th of 37 states and territories by count and 23rd of 37 per square mile.

Landslides and avalanches in Alaska, 1996 to 2026

Landslide records per year (NOAA Storm Events); 2026 to June 30, 2026.

recorded, no damage figure
under $1 million
$1 million or more
$10 million or more
$100 million or more, or 10 deaths
$1 billion or more, or 100 deaths
a year's colour: its recorded damage or deaths
a year with a death

Records: 1021996 to June 30, 2026
A year since 2000: 4.0average
Deaths: 5621 injuries
Damage, 2025 dollars: $43Mas filed
Busiest year: 200114 records

Source: NOAA NCEI Storm Events Database, records through June 30, 2026; deaths and damage as filed, damage in 2025 dollars. Search the record at NCEI.

Are landslide and avalanche records common in Alaska?

Alaska averages about 4.0 landslide and avalanche records a year since 2000, 7th of 37 states and territories by count. The busiest year on record was 2001 (14). Per 10,000 square miles of land, Alaska records 1.8 landslide and avalanche records since 1996, 23rd of 37 states and territories by that measure.

Source: NOAA NCEI Storm Events Database, records since 1996, per 10,000 square miles of land area (Census Bureau 2024 Gazetteer; places under 1,000 square miles not ranked). Damage colours: Storm Events damage, 2025 dollars.

Which counties in Alaska have the most landslide and avalanche records?

Per square mile, Anchorage Municipality leads Alaska: 26 days with a landslide or avalanche record since 1996, 15.2 per 1,000 square miles of land. By raw count, Valdez-Cordova Census Area has the most landslide records (28 since 1996); large counties collect more records simply by covering more ground, so the ranking counts days with a record per unit of area (a storm filed for several forecast zones adds several records but one day).

Source: NOAA NCEI Storm Events Database, days with a record in the county since 1996 per 1,000 square miles of land (Census Bureau 2024 Gazetteer); in brackets, the count of records.

When is the slide season in Alaska?

Alaska's landslide and avalanche records by month. The busiest month is February (23 records).

The values, month by month

Jan 15 · Feb 23 · Mar 12 · Apr 15 · May 1 · Jun 1 · Jul 0 · Aug 3 · Sep 5 · Oct 3 · Nov 10 · Dec 14 (records).

Source: NOAA NCEI Storm Events Database, records by the month they began, since 1996.

What were the deadliest landslide and avalanche records in Alaska?

Alaska: the storms with the most deaths since 1996
Date	Record	Killed	Injured	Damage
2023-11-20	Debris FlowWrangell One storm episode: 2 records in 2 places; the totals are the episode's. A hurricane-force 964 mb low lifted out of the North Pacific and into the Gulf of Alaska through the early morning hours of November 20, 2023. This low-pressure system continued on a north-northwest track, with the warm front moving over the southern and central Panhandle through the day and the front pushing north ...	6	1	$2.1M
1999-03-21	AvalancheCook Inlet · forecast zone Cook Inlet A tragic avalanche, adjacent to Turnagain Pass on Saturday, took the lives of 6 people. After days of searching by many volunteers, 5 bodies were recovered. The avalanche was triggered by snowmachiners 'high-marking' on the mountain slope during a warm, sunny day...after heavy snows several days before.	6	0	$44K
2015-08-18	Debris FlowSitka A strong cold front with sub-tropical moisture moved into the eastern gulf and moved over the coastal areas of Southeast Alaska. As the front approached the coastal area of Sitka very high rain rates were being reported across the area in the early morning hours which lasted less than 6 hours. In three hours the Sitka ...	3	0	$2.1M
2002-01-12	AvalancheValdez-Cordova Census Area and Matanuska-Susitna Borough · forecast zone Copper River Basin Three people were buried by an avalanche while snowmachining on an unsupported cornice. One was dug out of the snow by her husband.	2	1	$10K
2001-02-03	AvalancheAnchorage Municipality and Matanuska-Susitna Borough · forecast zone Matanuska Valley A group of snowmachiners Saturday triggered an avalanche on a slope south of Eureka, near the east fork of the Matanuska River. The avalanche killed two members of the group and slightly injured a third man, who was carried downslope and trapped beneath his snowmachine until he was freed.	2	1	–
2020-12-01	Debris FlowHaines One storm episode: 2 records in 2 places, 2020-12-01 to 2020-12-02; the totals are the episode's. A large plume of concentrated moisture or Atmospheric River (AR) with an associated low-pressure system moved across the Pacific Ocean and transported tropical moisture from the southwest which impacted Southeast Alaska (SEAK) from December 1st through December 2nd. This event brought widespread significant, and ...	2	0	$25M
2002-04-01	AvalancheAnchorage Municipality · forecast zone Anchorage Muni To Bird Creek 3 men snowshoeing in the mountains adjacent to Eagle River were caught in an avalanche. One escaped.	2	0	–
2024-08-25	Debris FlowKetchikan Shortly after 1500AKST on August 25th the larger of two landslides crossed the 3rd Avenue Bypass, a state road which is one of two routes for local traffic to get across town. There were 2 city employees that were working to clear culverts in their vehicle as the landslide occurred and killed the driver and ...	1	3	$3.8M
1999-04-29	AvalancheCopper River Basin · forecast zone Copper River Basin A slow moving slab avalanche swept Canadian mountaineer off a 20 to 30 degree slope and over a 1,000 to 1,500 foot drop. Slab apparently let go about 7 am Thursday, and was about 100 feet wide and 3 feet deep. Temperature at the time at altitude was about 5 degrees Fahrenheit and wind was calm. The 10,000 foot peak ...	1	2	–
1999-04-16	AvalancheSusitna Valley · forecast zone Susitna Valley Kenneth Hayes, 44, of Healy, Alaska was killed by an avalanche Friday afternoon. His body was recovered at about 10:30 am Saturday in the debris. Hayes was among 12 snowmachiners riding the "Big Notch in the Mountains" at Jack River Canyon, about 12 miles south of Cantwell, when a slide broke loose shortly before 4 ...	1	2	$5K

Source: NOAA NCEI Storm Events Database: deaths direct and indirect, as filed by the National Weather Service, summed over each storm (one episode, or one named storm filed by several offices). Storm names from the titles of FEMA declarations that name the storm's counties.

The costliest landslide and avalanche records in Alaska

Alaska: the most damaging storms since 1993, 2025 dollars
Date	Record	Killed	Injured	Damage
2020-12-01	Debris FlowHaines One storm episode: 2 records in 2 places, 2020-12-01 to 2020-12-02; the totals are the episode's.	2	0	$25M
2020-10-26	Debris FlowCraig	0	0	$4.9M
2024-08-25	Debris FlowKetchikan	1	3	$3.8M
2006-02-13	Debris FlowAleutians West Census Area · forecast zone Eastern Aleutians	0	0	$2.3M
2015-08-18	Debris FlowSitka	3	0	$2.1M
2023-11-20	Debris FlowWrangell One storm episode: 2 records in 2 places; the totals are the episode's.	6	1	$2.1M
2000-01-26	AvalancheValdez-Cordova Census Area and Yakutat City and Borough · forecast zone Central Gulf Coast	1	1	$857K
2019-10-06	Debris FlowDouglas	0	0	$735K

Source: NOAA NCEI Storm Events Database: property and crop damage as estimated by the National Weather Service, in 2025 dollars.

Are landslide and avalanche records becoming more frequent in Alaska?

Alaska's count per decade against the whole country's, and its share. NOAA recorded every event type only from 1996, so earlier decades are not comparable; the share of the national total is the fairer comparison across decades.

Landslides and avalanches: Alaska and the United States by decade (2020s to June 30, 2026)
Decade	Alaska	United States	Alaska's share
1996-99	13	98	13.3%
2000s	46	790	5.8%
2010s	17	1,304	1.3%
2020-26	26	1,224	2.1%

Source: NOAA NCEI Storm Events Database.

The most recent landslide and avalanche records in Alaska

The 12 most recent records, to June 30, 2026
Date	Record	Killed	Injured	Damage
2025-09-20	Debris FlowMendenhall Valley	0	0	$2K
2025-01-24	AvalancheNorth Slope Borough · forecast zone Central Brooks Range	0	0	–
2025-01-24	AvalancheDenali Borough · forecast zone Northern Denali Borough	0	0	–
2024-08-25	Debris FlowKetchikan	1	3	$3.8M
2023-11-20	Debris FlowWrangell	6	1	$1.5M
2023-11-20	Debris FlowKlawock	0	0	$534K
2020-12-02	Debris FlowSkagway	0	0	$1.6M
2020-12-01	Debris FlowHaines	2	0	$23M
2020-10-26	Debris FlowCraig	0	0	$4.9M
2020-03-09	AvalancheAnchorage Municipality and Matanuska-Susitna Borough · forecast zone Matanuska Valley	1	0	–
2020-02-25	AvalancheAleutians West Census Area · forecast zone Eastern Aleutians	1	0	–
2020-02-10	AvalancheKenai Peninsula Borough · forecast zone Kenai Peninsula	1	0	–

Source: NOAA NCEI Storm Events Database, records through June 30, 2026; the newest months are revised by NCEI as reports arrive. Search the record at NCEI.

Federal disaster declarations for landslide and avalanche records in Alaska

FEMA has declared 13 disasters in Alaska for landslide and avalanche, counting its incident type and declarations that name landslide or mudslide in the title (FEMA files most storm disasters under Severe Storm); 13 were major disasters, the latest on November 13, 2024.

The 12 most recent
Declared	Number	Title	Areas named
2024-11-13	DR-4846	Landslides	1
2024-04-06	DR-4767	Severe Storm, Flooding, and Landslides	3
2024-03-15	DR-4763	Severe Storm, Landslides, and Mudslides	2
2022-09-23	DR-4672	Severe Storm, Flooding, and Landslides	5
2022-07-26	DR-4661	Landslide	1
2022-01-15	DR-4638	Severe Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides	1
2021-02-17	DR-4585	Severe Storm, Flooding, Landslides, and Mudslides	5
2012-11-27	DR-4094	Severe Storm, Straight-Line Winds, Flooding, and Landslides	5
2009-12-18	DR-1865	Severe Storms, Flooding, Mudslides, and Rockslides	1
2008-09-26	DR-1796	Severe Storms, Flooding, Landslides, and Mudslides	4
2006-12-08	DR-1669	Severe Storms, Flooding, Landslides, and Mudslides	3
2006-10-16	DR-1663	Severe Storms, Flooding, Landslides, and Mudslides	3

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), through October 2, 2026. OpenFEMA dataset page.