Alaska, 2019Flood in Alaska, September 20 to 21, 2019
September 20 to 21, 2019 · NWS AJK · 1 event in 1 county or zone
A deep trough of low pressure with a long fetch from the North Pacific to the Gulf of Alaska produced a very strong and wet weather system. The atmospheric river slammed into northern southeast Alaska panhandle from September 20th through the 21st.
Every event with a place to put it. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
Open the live radar over this ground
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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.
A deep trough of low pressure with a long fetch from the North Pacific to the Gulf of Alaska produced a very strong and wet weather system. The atmospheric river slammed into northern southeast Alaska panhandle from September 20th through the 21st. The northern inner channels received moderate to heavy rainfall with stations reporting one to two inches of at sea level with more at higher elevations. Along with the heavy rainfall there was very high freezing levels which ranged from eight to ten thousand feet. These high freezing level accompanied with the heavy rain increased the runoff from any snow left in the mountains and ice melt from area glaciers. All of the rain and snow/ice melt produce moderate flooding along the Taiya River and flooded the Chilkoot trail, part of the Klondike Gold Rush National Historical Park, near Dyea Alaska. The river crested around seventeen point sixty-four feet which is above moderate flood stage of seventeen feet in morning hours of September 21st.
What forecasters said that day
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 Sep 20, 1:46 PM AKST, 5 hours 44 minutes earlier.
Area forecast discussion, Sep 20, 1:46 PM AKST, 5 hours 44 minutes before
Southeast Alaska Forecast Discussion
National Weather Service Juneau AK
246 PM AKDT Fri Sep 20 2019
.SHORT TERM...MIMIC indicated precipitable water traces a long
tentacle of subtropical moisture north-northeastward across the
North Pacific squarely into Southeast Alaska. Precipitable water
and IVT values for the Yakutat 12Z sounding are not record worthy,
but still are very near during one of our wettest times of year.
With the previous systems priming us, and a few before that, we
have reached the point of concern with minor flooding for the
Taiya River near Skagway, Montana Creek in Juneau, and the Indian
River in Sitka. Rainfall amounts of 1 to 2 more inches are
expected tonight with isolated amounts up to 3. Increasing
cyclonic curvature over the northern Panhandle at 500 mb also led
us earlier to increase winds through the Juneau area for gusts to
60 mph and for much of the rest of the Panhandle of 40 to 50 mph.
Winds will slowly come down at Juneau this evening but remain
strong over Haines, Skagway, and Ketchikan through early Saturday
morning.
Rainfall will turn more showery by Saturday as more unstable air
migrates in. Weak ridging will occur across our CWA through most
of the weekend, but continued southwesterly flow in the low levels
will allow for showers to continue during this time period.
Showers may become more scattered in nature, but QPF amounts are
still relatively high, in general to account for short-duration
more intense rainfall. The next big system arrives Sunday night
into Monday. This will bring another round of very strong winds
and heavy rainfall for much of the Panhandle.
No changes were made to the forecast so as to free staff to
monitor and react to the current dynamic system.
.LONG TERM.../Sunday through Friday as of 10 pm Thursday/
The weather will be most active during the first half of the long
range period, then a quieter pattern is becoming more likely
during the latter part. A strong occluded front will move NE into
the area Sun night into Mon. Looking like a significant low will
form and move NNE into the gulf by Mon morning, then curve back
to the W and merge with the original parent low that will be
moving E into the gulf during Mon. This combined low should move
across the gulf and through SE AK Tue. After that, there may be a
couple of weaker systems that might move in toward midweek, then
looking like late week into the weekend will see upper ridging
developing over much of the gulf and SE AK. Used mainly the 12z
GFS to handle things through 00z Tue, then WPC/NBM after that. Did
use 21z SREF to help with POPS through late Sun night.
One of the main model issues is how far E the developing low will
track before it curves back and merges with the parent low. 12z GFS
represented a middle ground compromise, taking low into the
central gulf, with the 12z Canadian further W and the 12z ECMWF
further E. The timing of the occluded front moving onshore was
slowed some. Overall, system looks fairly wet and windy, but with
the main upper level jet sinking S fairly early in the period, a
prolonged heavy rain event is less likely with the front. May get
some heavier precip Mon night into Tue as the combined low moves E
and onshore flow increases.
Precip chances look like they will decrease for the latter half
of the long term as upper ridging takes over across the area.
Still some important amplitude and positional differences to work
out with the placement of the ridge axis, so cannot completely
remove mention of precip further out yet.
&&
.AJK Watches/Warnings/Advisories...
PUBLIC...Strong Wind until 7 PM AKDT this evening for AKZ021-023-027.
High Wind Warning until 7 PM AKDT this evening for AKZ025.
Areal Flood Advisory until 10 PM AKDT this evening for AKZ025.
Areal Flood Advisory until 9 PM AKDT this evening for AKZ023.
Strong Wind until 7 PM AKDT this evening for AKZ017-020.
Strong Wind through late tonight for AKZ028.
Strong Wind through Saturday morning for AKZ019.
Areal Flood Advisory until 1 PM AKDT Saturday for AKZ018.
Strong Wind from 1 AM AKDT Saturday through Saturday morning for
AKZ018.
MARINE...Gale Warning for PKZ013-031>036.
Small Craft Advisory for PKZ011-012-021-022-041>043-051>053.
&&
JWA/RWT
Visit us at http://www.weather.gov/JuneauFlood, Taiya Inlet
- When
- September 20, 7:30 PM AKST to September 21, 1:30 PM AKST
- Where
- Taiya Inlet County, 2.66 mi NW of Skagway to 13.28 mi NW of Skagway
- Cause
- Heavy Rain
- Reported by
- River/Stream Gage
- Coordinates
- 59.482, -135.342
There was a rain event to prime soils a day before the flooding event after a very dry period for the northern inner channels of Southeast Alaska. Moderate to heavy rains moved over the area on September 20th. The high rain rates continued for the next forty-eight hours. Rainfall totals from this time frame ranged from one to two inches near sea level with higher amounts in the headwaters at higher elevations. The very warm temperatures created very high freezing levels that increase runoff from snow or ice melt. The Taiya River started to rise through the afternoon of September 20th and went above minor flood stage of sixteen point five feet by the early evening hours. The river continued to rise at steep fashion through the night and went above moderate flood stage of seventeen feet a little past midnight of September 21st. The Taiya River crested in the early morning of September 21st at seventeen point sixty-four feet. The rain slowly diminished through the rest of the morning hours and the river slowly receded to be below minor flood stage by the afternoon of September 21st. The National Park Service reported that there was some flooding Chilkoot trail.
- Flood
- Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.
After NWS Directive 10-1605, the rules offices file Storm Data by.
- Tornado and Flash Flooding in North Dakota, September 20 to 21, 2019$72 million · EF0 · 25 events
- Flash Flooding and Hail in Minnesota, September 20 to 21, 2019$21 million · 1.25 in hail · 7 events
- High Surf in Florida, September 20, 20191 death · 1 event
- Flash Flooding and Hail in North Dakota, September 20 to 21, 2019$1.9 million · 2.75 in hail · 17 events
- Marine Thunderstorm Winds in Gulf of Mexico, September 20 to 22, 201944 events
- Flash Flood in Missouri, September 20, 2019$20,000 · 1 event
- Hail in North Dakota, September 20, 20191.5 in hail · 11 events
- Tornado and Hail in Nebraska, September 20, 20191.75 in hail · 10 events
- Hail and Damaging Wind in South Dakota, September 20, 20191.5 in hail · 6 events
- Hail and Damaging Wind in Minnesota, September 20, 20191.75 in hail · 5 events
- Hail in Wyoming, September 20, 20191.75 in hail · 5 events
- Damaging Winds in South Dakota, September 20, 201957 kt wind · 5 events
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: 857412.