Complex low pressure presisted over the entire Gulf on 4/9 & 4/10. A very strong wave developed south of Haida Gwaii and skirted the coast of SE Alaska causing storm force wind and hurricane force gusts.
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.
Complex low pressure presisted over the entire Gulf on 4/9 & 4/10. A very strong wave developed south of Haida Gwaii and skirted the coast of SE Alaska causing storm force wind and hurricane force gusts. There was some damage reported, and the peak wind was 100 MPH. The strong wave moved off the coast and into the western Gulf on the morning of 4/11.
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 Apr 10, 10:32 AM AKST, 2 hours 28 minutes earlier.
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
1132 AM AKDT Tue Apr 10 2018
.UPDATE...With a choir of models singing ominous tunes of a robust
70-kt low level jet at 925 mb, our confidence has risen to the
point of posting a late breaking High Wind Warning for 60 to 70
mph gust for portions of the southern Inner Channels, the
southeast Gulf Coast, and the eastern Gulf Coast. In anticipation,
we have also raised wind speeds through Clarence Strait to 50 kt.
Behind the system at Buoy 46207 south of Haida Gwaii, pressure
rises of 8 mb in a single hour cast shadows of an intensely
menacing system. MOS and some of the higher resolution models
have been slower to capture this highly dynamic and developing
system, and thus we could only slowly increase winds. However,
forward thinking colleagues on previous shifts very astutely noted
the potential with a special weather statement earlier this
morning and set the ground game to warn of impactful high winds.
The warned area includes the population centers of Ketchikan,
Sitka, Metlakatla, Craig, Thorne Bay, Klawock, and Hydaburg as
well as several smaller adjacent towns. Winds will begin first in
the far south mid-afternoon and then quickly lift northwestward to
affect Baranof Island by later this afternoon, potentially
persisting into mid-evening. Therefore, Baranof Island was
separated with later impact times. Be prepared for impacts to all
sorts of transportation. Power outages will be possible due to
downed tree branches. Loose items will be blown around in the wind
and larger unsecured objects could be displaced by the wind.
Persons outdoors should be aware of flying debris. While areas in
the north-central and south-central interior Panhandle may see
some gusty winds this evening, our focus today and this evening
will squarely be on the far south and Baranof Island.
&&
.PREV DISCUSSION......ISSUED AT ...610 AM Tue APR 10 2018
SHORT TERM...A strong low over the western gulf has a large
occluded front wrapped around it and extending over the eastern
gulf. The low center will remain on the west side of the gulf and
start to weaken today. A wave along the front is causing a new
low to form south of Haida Gwaii as seen on satellite imagery as
of 530am. This feature looks to track across the eastern gulf
outside waters, starting near Dixon Entrance late Tuesday
afternoon and ending up over the north-central gulf by Wednesday
morning. In general, models came into better agreement on this new
low center developing and tracking quickly across the area.
Therefore have increased winds speeds quite a bit to reflect this
new thinking. Majority of the panhandle will see wind gusts of
35-45mph for a short period of time. Some places along the outer
coast, including Port Alexander and portions of POW Island could
see higher gusts. Peak winds for the southern inner channels look
to be during the late afternoon and in the early evening for S.
Baranof Island. The Icy Strait area, including Tenakee Springs,
will get into the action in the late evening. Yakutat can expect
strong gusts overnight and into the pre-dawn hours.
Expect rain to be pretty spotty today, especially over the
northern panhandle. The southern areas will see the threat of rain
increase as the low approaches in the afternoon. Rain will spread
across the region tonight, but similarly to the wind, will be
moving in/out quickly. Cloudy skies and gusty winds through
tonight will likely keep the diurnal temperature range smaller
than we've seen as of late, likely less than 10 degrees. This area
of the forecast was not given as much attention.
On Wednesday expect more breaks in the cloud cover and a lower
chance of rain. There will continue to be multiple lows in the
gulf, rotating about a larger parent low, but overall flow across
the panhandle will become more offshore.
While the model upper level pattern is fairly similar,
there are differences with strength near the surface for today's
low. Initially the ECMWF looks to be the strongest/fastest, the
Canadian is the slowest to move the feature through but is also
fairly strong. The new 6z NAM came into better agreement with the
GFS which was in the middle as far as placement goes. Ended up
using primarily the GFS with some NAM for changes to the low
placement and to increase wind speeds. The ECMWF and Canadian
models had the low center closer to shore, this would result in
stronger winds. This system will be closely monitored for
more/less development or for position changes.
LONG TERM /Thursday through Tuesday/...As of 10pm Sunday.
Remnants of the mid/upper trough currently over the extreme
southern Gulf will wind up along the southern Panhandle coast by
early Thursday. Part of this energy will likely be pulled N and
then W around a second closed mid/upper trough which will
establish itself over the south central Gulf by Thursday night.
Operational models and their ensembles continue to differ in the
details of individual fronts and pieces of energy rotating
northward around this trough through early Saturday. Most likely
places to receive continued rainy conditions and periods of gusty
wind from Thursday through Saturday will be the southern
Panhandle, although most of the Panhandle will probably see
rainfall on Friday as the main upper trough begins to get kicked
east. The biggest disagreement in model-land centers around what
happens with the Arctic stream trough forecast to drop southward
through the Yukon and interior of Alaska on Friday and Saturday as
ridging builds over the Bering Sea. Timing and position of this
feature will likely determine how quickly the low level flow gains
an offshore component this weekend and the resultant drying.
Eventually though, it looks like a drier period will begin to set
up by Sunday into Monday.
&&
.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind from 4 PM this afternoon to 10 PM AKDT this evening
for AKZ026.
High Wind Warning from 2 PM this afternoon to 7 PM AKDT this
evening for AKZ027-028.
Strong Wind until 10 PM AKDT this evening for AKZ025.
Strong Wind from 7 PM AKDT this evening through late tonight for
AKZ021-022.
High Wind Warning from 5 PM this afternoon to 10 PM AKDT this
evening for AKZ023.
Strong Wind late tonight for AKZ017.
MARINE...Storm Warning for PKZ036.
Gale Warning for PKZ022-032-033-041>043-051-052.
Small Craft Advisory for PKZ011>013-021-031-034-035-053.
&&
JWA/Ferrin/DEL
Visit us at http://www.weather.gov/JuneauSpecial Weather Statement National Weather Service Juneau AK 1111 AM AKDT Tue Apr 10 2018 AKZ017-021-022-025-026-110800- Cape Fairweather to Cape Suckling Coastal Area- Eastern Chichagof Island- Salisbury Sound to Cape Fairweather Coastal Area- Juneau Borough and Northern Admiralty Island- Inner Channels from Kupreanof Island to Etolin Island- Including the cities of Yakutat, Hoonah, Elfin Cove, Pelican, Juneau, Petersburg, Wrangell, and Kake 1111 AM AKDT Tue Apr 10 2018 ...FAST MOVING STRONG LOW TO AFFECT THE PANHANDLE LATE TUESDAY AFTERNOON AND TUESDAY NIGHT... A strong low is forming late this morning south of Haida Gwaii. This low will deepen rapidly as it tracks north today and will pass close by the southern outer coast late this afternoon. The low will then track northwest into the north-central gulf late tonight. Strong winds are expected across much of the central panhandle and northeast gulf coast tonight. Because this system is moving so quickly, the period of strongest winds for any given location will last only 3 to 6 hours. At this time, peak wind gusts are forecast to be around 45 mph. However, there is some uncertainty with the exact track and strength of this low, and higher winds cannot be ruled out at present. Therefore, residents of the central panhandle and the northeast gulf coast of Alaska are urged to remain alert for updates to the forecast as the day progresses.
4 high wind. Local standard time, as filed.
Klawock Airport had a measured gust 58 mph. Forecasters at the Juneau Office cannot recall seeing that so high. Hydaburg AWOS was out of service. Cape Decision had several measured gusts around 74 mph. No damage has been reported so far.
Two Marine Exchange sites around Ketchikan had measured gusts to 100 mph on 4/10. Annette Airport had gusts to 62 mph. Many areas reported gusts 60 to 70 mph. Several downed power lines caused widespread power outages according to the local utility. At Metlakatla, a couple of buildings were moved off their foundations.
Highest wind at Sitka Airport was only 44 mph around 1900 AKST on 4/10. Cape Decision had gusts to 77 MPH. Port Alex had some wind with branches down but no measurements|due to the tide gauge met data being blocked by a building.
Darlene in Pt. Baker called in with a wind report of really strong 'circling' winds, was having issues getting up to the runners with the work skiff. Estimate of 55-60 mph. |More, more, more. Dish blew off. Roof damage. Susan Wise Eagle
-|High Speed Wind: 50 mph|Wind Damage: Cedar shakes and tarpaper blew off neighbor's|roof. Satellite dish blew down and smashed windshield of truck|parked below. Limbs blew down across Zimovia Hwy.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2018Every state in 2018This day in weather historyWarnings in Alaska, April 2018
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: 739296, 739297, 739298, 739299.