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 through the evening hours. There was a cold air mass over the northern half of the region with a stalled Arctic front over the central Panhandle. This cold air over the northern Panhandle and the Yukon produced strong high pressure over the Yukon, creating a tight pressure gradient over Southeast Alaska. This weather system also had significant subtropical moisture associated with it and characteristics of an atmospheric river with most of the moisture transport going over the southern half of the panhandle.
As the associated weather front moved over Southeast Alaska through November 20th, the cold air in place over the northern half of the panhandle and a strong high pressure in Canada produced a very strong pressure gradient. This set up an overrunning snowfall event with an excess of 12 inches and with the combination of strong to high winds produced blizzard conditions and the development of a mountain wave event near downtown Juneau. Most of the winter impacts occurred over the northern half of Southeast Alaska. Over the southern half of the panhandle there was shallow cold air in place which did produce some snow at the start of the event in the evening hours of November 19th into the early morning of the 20th. The snow changed over to rain as the warm air associated with the atmospheric river moved over the region along with high winds. Heavy rain moved over Prince of Wales Island (POW) and the southern half of Southeast Alaska in the morning hours of November 20th and by the end of the day rain amounts ranged from over 6 inches on the western side of POW to 3 inches on the eastern side of the island and over the southern inner channels. This produced minor flooding near Thorne River as the river went over its banks and flooded the main road that accesses the town of Thorne Bay from the afternoon hours of the 20th and receded below its banks in the late morning of the 21st. There were reports of roads damaged by culverts washing out due to the heavy precipitation near Coffman Cove. This affected several homes and cut off access by car to the rest of the island.
The rainfall rates that moved over the southern half of the panhandle were very high and ranged from 0.35 to 0.75 inches per hour. This intense precipitation persisted, resulting in impressive 3-hour, 6-hour, and 24-hour rainfall totals and precipitation frequencies. The precipitation frequencies ranged from 10 to 50 year rainfall event. The combination of these very high rain rates and high winds produced widespread shallow landslides across POW and a deadly one near Wrangell.

Blizzard in CITY AND BOROUGH OF JUNEAU, ALASKA
From 20-NOV-23 04:12:00 to 20-NOV-23 21:42:00 (AKST-9)
Crop damage: 0.00K
Reported by: Local Official

Mesonet stations, webcams, and officials in downtown Juneau confirmed high winds, alongside significantly reduced visibility in downtown Juneau due to falling and blowing snow. A Taku mountain wave event cause wind gusts over downtown Juneau in excess of 60 mph for 16 hours including a peak gust of 90 mph on top of the downtown library at 623pm. A power outage was reported by an off duty NWS Employee at 831am, and Juneau Harbors posted a picture of a sunken vessel in a downtown harbor on social media. The City of Juneau closed at 11am due to high winds and blizzard conditions, and the Juneau school district announced schools would have an early release. State offices were closed, as were the UAS campus buildings. Meanwhile, the north side of the community, between Auke Bay and Tee Harbor, saw 6-10 inches by 2pm and a storm total of 12 -14 inches. Snow began to mix with rain between 12-3am.

Debris Flow in CRAIG COASTAL, ALASKA
From 20-NOV-23 07:00:00 to 20-NOV-23 22:00:00 (AKST-9)
Location: KLAWOCK
Flood cause: Heavy Rain
Property damage: 551.00K
Crop damage: 0.00K
Reported by: Social Media

Reports began coming in of landslides near the Klawock airport, close to Black Bear Creek, and near Craig in the mid morning hours of November 20th. As the day progressed, more landslides were reported across Prince of Wales Island, including along the Hollis Highway, near Hydaburg, and along Port Saint Nicholas Road. In Coffman Cove, roads were reported to be washed out, and a landslide blocked the road leading to Luck Lake. Some homes were impacted, but for the most part the landslides blocked roadways and impacted travel.
In addition to the heavy rain, the maximum sustained wind measured at the Kasaan FAA webcam was 51 mph at 350pm, a peak wind gust of 59 mph measured at the Thorne River RAWS at 554pm, and peak gusts of 55 mph were measured at Craig and Klawock between 4-6pm. At 5pm there was a report of power poles snapped in half in Hydaburg followed by a report of roofs blown off and flying debris in the same community at 631pm. There were other reports of trees down across the island and the local ferry service to Ketchikan was cancelled.

High Wind in ANNETTE ISLAND, ALASKA
From 20-NOV-23 07:53:00 to 20-NOV-23 16:00:00 (AKST-9)
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

During a high wind event, the Metlakatla AWOS reported wind gusts as high as 63 mph. An NWS employee reported a rooftop wind gust of 64 mph. These winds resulted in an extended power outage due to a tree hitting a power line shortly before 2pm. Power was restored to the community approximately 24 hours later.

Winter Storm in HAINES BOROUGH AND KLUKWAN, ALASKA
From 20-NOV-23 09:00:00 to 21-NOV-23 22:30:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Utility Company

At 1145am on the 20th, downed power lines were reported by a utility company (AP&T) on Beach Road and winds kept work from being done through the next day. At 1242pm, snowfall rates caused Haines Police to advice the public to stay off the roads and at 237pm DOT estimated 4-8 inches of snow had fallen. By 657pm, 8 inches were measured in town and by by 1038pm 15.5 inches were measured near 26 mile. Storm totals from COOP observers and spotters over the 36 hour event ranged from 23 to 29 inches across the borough. Additional spotter reports indicated that much of the snow fell through the afternoon hours of the November 20th with another burst of heavy snow mid-day on the 21st. Spotters also noted a very high ratio, making it easier to move. Haines school had early dismissal on Monday. The borough offices and school were closed for Tuesday. A glaze was reported in town as the snow ended at approximately 1030pm on the 21st.

Winter Storm in ADMIRALTY ISLAND, ALASKA
From 20-NOV-23 02:47:00 to 20-NOV-23 19:00:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The Angoon Seaplane base AWOS recorded heavy snow with a quarter mile visibility or less between 740am and 450pm on the 20th. Winds during this time were gusting to around 25 mph. A citizen called at 1030am to report the whiteout conditions. The AWOS stopped reporting at approximately 7pm, indicating a possible power outage or communications failure. Per a social media post at 533pm, at least 16 inches of new snow fell in the City of Angoon.

Winter Storm in WESTERN KUPREANOF ISLAND AND KUIU ISLAND, ALASKA
From 20-NOV-23 02:30:00 to 20-NOV-23 15:00:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter in Security Bay, SW of Kake, received 6 inches of wet snow by 7am on the 20th. At 3pm the total was up to 16 inches and changed to heavy rain. No reports were received from the community of Kake or Port Alexander.

High Wind in KETCHIKAN GATEWAY BOROUGH, ALASKA
From 20-NOV-23 07:33:00 to 20-NOV-23 20:13:00 (AKST-9)
Magnitude: 65.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Marine Exchange of Alaska mesonet station at Salmon Landing measured a gust of 67 mph at 733am on the 20th and continued to periodically reach high wind through 813pm. Peak winds were observed in Ward Cove with a gust of 75 mph at 744pm. Other mesonet stations reached near or above high wind criteria across Revillagigedo Island, with a peak wind gust of 58 mph reported by the Ketchikan ASOS at 510pm. Heavy rain in addition to the winds caused a tree to slide down a slope near Ward Cove that was reported around 1155am and other power outages were reported in the area.

Winter Storm in GLACIER BAY, ALASKA
From 20-NOV-23 05:56:00 to 21-NOV-23 03:30:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported that 15 inches of new snow fell in Gustavus, with snowfall changing over to rain at of the time of the observation. Earlier, a trained spotter reported 8 inches of snow had fallen by 220pm on the 20th, with snow still falling at the time of observation.

Winter Storm in CAPE FAIRWEATHER TO LISIANSKI STRAIT, ALASKA
From 20-NOV-23 05:00:00 to 21-NOV-23 05:00:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A total of approximately 18 inches of snow (17.8) was measured by a COOP observer in Pelican throughout the duration of a winter storm. Earlier during the event, a social media report was received of 16 inches of snow having fallen as of 542 PM on November 20, with snow still falling at the time of observation.

Winter Storm in EASTERN CHICHAGOF ISLAND, ALASKA
From 20-NOV-23 05:44:00 to 21-NOV-23 04:56:00 (AKST-9)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A trained COOP observer reports that a total of approximately 25 inches of snow fell through the duration of a major weather system. As early as 12:45 PM on November 20, a social media report of 12 to 15 inches of new snow in Hoonah was received, with snow still falling at the time. Whiteout conditions were reported at 944am on the 20th.

Debris Flow in WRANGELL CHANNELS, ALASKA
From 20-NOV-23 20:00:00 to 20-NOV-23 23:59:00 (AKST-9)
Location: WRANGELL
Flood cause: Heavy Rain
Property damage: 1.60M
Crop damage: 0.00K
Reported by: Law Enforcement

By the early evening as the front was moving eastward a landslide was reported near mile post 11 south of Wrangell along the Zimovia Highway, which blocked the road and cut power to residents on the other side of the slide. The landslide resulted in 6 people perishing and 3 homes being destroyed, one person survived as they were saved by search and rescue personnel. The area around the slide was evacuated and homes to the south of the slide were without power for multiple days. Supplies were brought to the cutoff homes via boat.
Rain amounts around Wrangell were around 3 inches for 24 hours but half of that amount fell within 6 hours preceding the landslide being reported along with high wind gusts at a 900 foot weather station just west of Wrangell on Zarembo Island. There was another large landslide that came down on the next ridge to the east along the Middle Ridge forest service road. This blocked the road and a person had to spend the night in his car as the road was blocked in both directions.