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.
Every event with a place to put it; 9 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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 AJK wrote it up.
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.
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 Juneau, AK wrote its last area forecast discussion before the first event at Nov 19, 4:55 PM AKST, 9 hours 35 minutes earlier.
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
455 PM AKST Sun Nov 19 2023
.SHORT TERM...A very strong system advancing into the panhandle
will bring hurricane force winds to parts of the outer coastal
waters, high winds to parts of the panhandle, winter storm and
blizzard conditions to other parts of SE AK, and significant
amounts of rainfall to others through the next few days.
As of Monday evening, high pressure over the Yukon is working in
concert with a strong low advancing N towards the Gulf of AK to
strengthen the pressure gradient across the panhandle. This will
lead to a period of strong outflow winds, as an early season
northerly outflow event initiates Monday night. These outflow
winds will encourage significant cold air advection, as the
continental air mass normally located on on the Canadian side of
the coast mountains will successfully breach the mountain passes.
This will result in gale force winds and storm force winds across
the inner channels and outer coastal waters.
Concurrently, the scattered snow and rain showers across the
panhandle will to give way to more organized precipitation as the
low in the North Pacific advances into the Gulf. An occluding warm
front associated with the low will begin to move into the
southern panhandle Monday night. For the southern panhandle, this
will primarily be a rain and wind event. A High Wind Warning has
been issued for Prince of Wales Island, Annette Island, and
Ketchikan. Given the respectable amount of warm air advection and
fairly highly IVT values, opted to increase the total QPF for
these areas. Consequently, rainfall totals of between 2 to 3
inches near sea level with this system are anticipated across much
of the southern panhandle, and some river rises will occur.
As the system moves North, it will begin to overrun the
significantly cooler air from the outflow event which will
initiate an overrunning event. Although some snow accumulation is
possible for locations including Petersburg and Kake, anticipate
that the corresponding warm air advection with the system will
likely succeed in causing a rain snow changeover fairly early on,
and so have held these areas at a Winter Weather Advisory. it
should be noted that there is at least some chance Petersburg,
especially along the Mitkof Highway, could remain snow longer than
currently forecast, but at this time think this is the less likely
scenario.
As the system continues to advance North, the warm air advection
will increasingly struggle to push past the cold air outflow,
resulting in increasingly long periods of snowfall. Anticipate
that snow will begin through the early morning for places like
Angoon, before beginning during the morning proper for places like
Juneau, Hoonah, and Gustavus. While snow may initially be fairly
light, rates will rapidly increase and the greatest snowfall rates
for these locations will occur late Monday morning through Monday
afternoon. Gusty winds will also be present in these places, and
in Juneau, the oncoming system will collide directly with a
developing Taku Wind Event initiated by the northerly outflow.
This will result in significant reductions on visibility, and a
Blizzard has been issued for Juneau, alongside Winter Storm
Warnings across the Icy Strait Corridor. Snowfall rates will
diminish Monday night through Tuesday morning as the warm air
advection finally manages to reach the surface and overpower the
cold air advection. This will result in a changeover to a more
rain snow mix.
As the system continues to move North, it ultimately reaches the
northern panhandle. Anticipate that Haines, Skagway, and their
associated highways will see snow beginning later Monday morning
and see snowfall lasting through Tuesday morning. The Haines and
Klondike Highways will likely see the greatest snowfall totals
for the northern panhandle. In the wake of the system, anticipate
conditions improving for most locations through Tuesday, though
rain and snow showers will continue to move across the panhandle.
.LONG TERM.../Tuesday through Friday morning/ Mid range forecast
remains largely unchanged in the wake of the impactful wind and snow
event Monday. As mentioned in the short range, the storm force low
in the Gulf is still expected to move north and turn northwest on
Tuesday. Outflow winds will continue through Tuesday, and combined
with the storm force low in the Gulf, will result in continued gales
for most of the central and northern inside waters through Tuesday
morning. Otherwise winds throughout the inner channels will begin
to slacken Tuesday into Wednesday. As the low in the Gulf pushes
off to the west, rain and snow showers will continue across the
panhandle for the majority of the week with persistent southerly
onshore flow and a quasi stalled boundary. Overall looking to be
progressively relatively warmer from south to north for most of
the panhandle for the second half of the week as well.
&&
.AVIATION.../Until 00Z Tuesday/...CIG and VIS flight conditions
will deteriorate over the Panhandle and Inner Channels to between
MVFR and IFR and wind conditions will drastically deteriorate, as
well, as a storm to hurricane force frontal system moves up from
the south through the 24-hour TAF period. Those conditions will
progressively deteriorate from south to north out ahead and
along with the front starting around 06Z late this evening for
the southern Panhandle and starting around tomorrow morning for
the northern third of the Panhandle. Primarily snow will impact
the northern half to 2/3 of the Panhandle, and primarily rain will
impact the southern third to half of the Panhandle. As for winds,
the NE to SW pressure gradient will significantly tighten as the
front pushes northward starting late this evening and rapidly
increase the winds as we approach 00Z Tuesday. Copious amounts of
LLWS out of the NE for the northern third of the Panhandle and out
of the SE of the southern 2/3 of the Panhandle and strong SFC
winds will have spread over the entire Southeast Alaska region
associated with the aforementioned front by late tonight/early
Monday morning.
&&
.MARINE...Hurricane and storm force winds across the outer coastal
waters and the Gulf of Alaska, alongside storm force and gale
force winds for the inner channels. Wave heights will be
significantly elevated, reaching above 35 ft in the Gulf,
alongside fully developed seas for many of the inner channels.
&&
.AJK WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Strong Wind from midnight AKST tonight through Monday morning
for AKZ318.
Winter Storm Warning from 9 AM Monday to 3 PM AKST Tuesday for
AKZ318-319.
Winter Storm Warning from 3 AM Monday to 3 AM AKST Tuesday for
AKZ320>322.
Winter Storm Warning from 3 AM to 9 PM AKST Monday for AKZ324.
Blizzard Warning from 6 AM Monday to 6 AM AKST Tuesday for
AKZ325.
Winter Weather Advisory from midnight tonight to noon AKST
Monday for AKZ326-327.
High Wind Warning from 6 AM Monday to midnight AKST Monday night
for AKZ328-330-332.
MARINE...Hurricane Force Wind Warning for PKZ644-663-664.
Storm Warning for PKZ012-022-053-642-643-651-661-662-671-672.
Gale Warning for PKZ011-013-021-031-032-035-036-641.
Small Craft Advisory for PKZ033-034-652.
&&
SHORT TERM...GFS
LONG TERM....STJ
AVIATION...JLC
Visit us at http://www.weather.gov/JuneauThe national radar mosaic for the moment the first event began.
6 winter storm, 2 debris flow, 2 high wind, 1 blizzard. Local standard time, as filed.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Debris Flow, Wrangell Channels | 2023-11-20 | 11 | Female | Permanent Home | Direct |
| Debris Flow, Wrangell Channels | 2023-11-20 | 44 | Male | Permanent Home | Direct |
| Debris Flow, Wrangell Channels | 2023-11-20 | 36 | Female | Permanent Home | Direct |
| Debris Flow, Wrangell Channels | 2023-11-20 | 16 | Female | Permanent Home | Direct |
| Debris Flow, Wrangell Channels | 2023-11-20 | 12 | Male | Permanent Home | Direct |
| Debris Flow, Wrangell Channels | 2023-11-20 | 65 | Male | Permanent Home | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2023Every state in 2023This day in weather historyWarnings in Alaska, November 2023
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: 1146763, 1146699, 1146698, 1146762, 1146761, 1146363, 1148551, 1146371, 1146856, 1146890, 1148560.