A storm system in the Gulf of Alaska sent a front northward onshore southern Alaska. The moisture associated with the front moving northward and a tight pressure gradient across the southern Copper River Basin resulted in strong gusty winds along with falling snow causing significant blowing snow conditions, especially through Thompson Pass.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS AFC wrote it up.
A storm system in the Gulf of Alaska sent a front northward onshore southern Alaska. The moisture associated with the front moving northward and a tight pressure gradient across the southern Copper River Basin resulted in strong gusty winds along with falling snow causing significant blowing snow conditions, especially through Thompson Pass. This resulted in very low visibilities to a half mile or less throughout the duration of the event.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Anchorage, AK wrote its last area forecast discussion before the first event at Nov 19, 4:45 AM AKST, 11 hours 19 minutes earlier.
Southcentral and Southwest Alaska Forecast Discussion National Weather Service Anchorage AK 445 AM AKST Fri Nov 19 2021 .ANALYSIS AND UPPER LEVELS... A large upper level low is continuing east along with a weakening surface low heading towards the Southeast Panhandle. Gap winds due to the tightened pressure gradient along the Gulf coast are also weakening gradually as reinforced cold air advection slowly mixes out. A North Pacific low is strengthening and moving into the western Gulf. A compact surface low is located over the western Aleutians moving east and bringing moderate rain to the region. && .MODEL DISCUSSION... Overall agreement points toward a new weather pattern developing this weekend. A North Pacific low will move northward and is expecting to interact with the Aleutian low. Once the Pacific low reaches the Aleutians and Western Gulf into Saturday morning, models align with this North Pacific low becoming the dominant system and the Aleutian low decaying. The low will move south of Kodiak Island before elongating and track towards the Northern Gulf. Snow totals for Kodiak indicate some model disagreement and forecast confidence is uncertain. The resulting depth and any nudges of the low centers to the east or west could influence the placement of the warm sector and the precipitation totals through the weekend. Precipitation along with gust easterly winds are expected. Precipitation type also remains somewhat uncertain. The models predominantly indicate snow due to colder air aloft, however given the warm sea surface temperatures and the long fetch over warmer water streaming into Kodiak, brief periods of mixed precipitation remain possible. Towards the end of the weekend when this low tracks into the Northern Gulf, confidence is high for stronger easterly winds to develop near the coast ahead of its associated front. The duration and timing of precipitation will depend on the exact position of the low center. && .AVIATION... PANC...VFR conditions and light winds will continue through Saturday morning. && .SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3: Friday and Sunday)... Conditions will remain clear and very cold across much of Southcentral through Friday with high pressure anchored over the Al-Can border. A broad trough will linger across the northern Gulf this morning, allowing for gap winds to continue. These winds, however, have waned overnight and will continue to trend downward through the day as both the trough and surface low east of the Copper River Delta weaken. The pattern then begins to get more active for the weekend as a North Pacific low lifts north toward Kodiak Island. This feature will lift a front across the Gulf with snow developing for Kodiak Island and Kodiak City by mid-morning Saturday. Northeasterly winds along the front will quickly ramp up as well, with gusts over 50 mph expected along the eastern coast of Kodiak Island. Recent model runs have come into better agreement with regard to the track of this system, but the question of just how much influence the warm sea surface temperatures will have on the surface temperatures for locations such as Kodiak City remains uncertain. Guidance briefly stalls the low south of Kodiak Island before moving it northeast near Middleton Island by late Sunday. This track will likely keep winds along the Kodiak Island coast more north-northeasterly, allowing colder air to remain in place. However, with sea surface temperatures hovering between 40 and 42 degrees, any prolonged northeasterly flow may drive temperatures in Kodiak City from the lower 30s into the mid 30s and allow for at least a mix of rain and snow, if not a complete changeover to rain by Saturday afternoon. Even with the uncertainty in max temperature, there will likely be a period of snow in conjunction with strong winds during the onset of the event and again toward the end of the event as colder air wraps in behind the low. The combination of snow and wind could reduce visibilities at times due to blowing snow. Kodiak City could see upwards of 6 inches of snow with this event, with lesser amounts if any rain does mix with snow. The front moves north by early Sunday morning with snow developing along the Southcentral coast. Snow with gusty winds are likely for Cordova with snow and blowing snow likely for Thompson Pass. Again, snow amounts in Cordova will be dependent on how much warmer, marine air advects over the immediate coast. The precipitation will linger through Sunday for Cordova and Valdez, with snow developing across the Copper River Basin and eastern Kenai Peninsula by late Sunday morning. While a few inches of snow are possible across the Copper River Basin, upwards of a foot or more of snow is possible for Whittier and Portage Valley. Snow will continue for these locations through Monday with snow possibly overspreading the Anchorage Bowl and western Kenai Peninsula. && .SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)... A quiet and cold pattern will continue across Southwest Alaska over the next few days as the dry and cold offshore flow pattern continues. Radiational cooling is expected to continue across the lower Kuskokwim Valley during the nocturnal hours as clear skies and light winds will continue. Temperatures will be slightly warmer over the Kuskokwim Delta due to brisk northeasterly winds. Nighttime low temperatures will range between -10F and -20F across the lower Kuskokwim Valley, 0F and -10F across the Kuskokwim Delta and 0F and -5F across Bristol Bay. && .SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)... An active weather pattern continues across the Bering/Aleutians as a gale force low continues to linger around the central Aleutians. Widespread areas of gale force winds will continue across the central and western Bering Sea today and tonight. Winds will begin to gradually ease to below gale force across the western and central Bering Sea Saturday morning as this low moves southeastward into the North Pacific. Winds will strengthen across the coastal waters south of the Alaska Peninsula and eastern Aleutians on Saturday as this low strengthens while moving into the Gulf. Large long period swell in the central Bering will gradually avate on Saturday due to the easing of the easterly winds. Widespread gale force winds with localized areas of storm force winds are likely across the coastal waters south of the Alaska Peninsula on Saturday and Saturday night before gradually easing on Sunday. && .MARINE (Days 3 through 5: Saturday through Monday)... Gulf of Alaska... A front with a triple point low is expected to move into the Gulf with gale force winds across the southern Gulf by Saturday morning. Sunday this system will move across the northern Gulf with gales possible across the Gulf. Monday the low will weaken with winds small craft or less across the area. However, there is a lot of uncertainty of the strength and track of the low in the Gulf Saturday through Monday. Seas will remain below 20 feet. Aleutians/Bering...A front will stall across the southern Bering on Saturday with gales expected along and north of the front. These winds will weaken Saturday night and Sunday to small crafts and less. Meanwhile, a low will track south of the Aleutian chain Saturday and towards the north Pacific by Sunday. Expect gales north of the low along the Aleutian chain and the AKPen on Saturday weakening to small crafts or less by Sunday. By Monday another north Pacific low moves south of the Aleutians spreading gales along the western and central Aleutians. Seas will remain below 20 feet. && .Long Term Discussion (Days 4 through 7: Sunday through Wednesday)... There is increasing model spread for the extended period, largely due to differences in interaction between an Arctic trough digging southward across mainland Alaska and a trough crossing the North Pacific and headed toward the Gulf of Alaska. The key will be timing and spacing of these troughs, which will determine whether they remain separate or whether they interact, with phasing of short-waves. The commonality in all solutions is the development of a very large closed upper low centered over Southwest Alaska. So, what does this mean for the weather. Arctic air will be firmly entrenched across much of Alaska, including the Bering Sea and Aleutians. The storm track will be centered across the North Pacific and into the Gulf of Alaska. Depending on the evolution of the upper level pattern, storms crossing the Gulf could impact Southcentral (which would also moderate temperatures) or they could remain farther south and track toward Southeast Alaska. For now, based on ensemble guidance, will keep most of the region cold and dry, with the best chance of precipitation across Kodiak and the Gulf coast. && .AFC WATCHES/WARNINGS/ADVISORIES... PUBLIC...Wind Chill Advisory: 131 135 MARINE...Heavy Freezing Spray: 119 127 139 140 160 180 181 Storm Warning: 131 132 136 138 150 351 352 Gale Warning: 119 120 127 130 137 139 155 165 177 179 185 411-414 FIRE WEATHER...NONE. && SYNOPSIS AND MODEL DISCUSSION...VR/AP SOUTHCENTRAL ALASKA...TM SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...ED MARINE/LONG TERM...CJ/SEB
1 winter storm. Local standard time, as filed.
Webcams through the FAA showed fairly low visibilities through Thompson Pass as a result of the falling snow and strong gusty winds. Conditions remained unchanged for hours resulting in treacherous and dangerous travel conditions through Thompson Pass from the afternoon of the 19th into the early morning of the 20th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2021Every state in 2021This day in weather historyWarnings in Alaska, November 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1001867.