A cold front brought in unseasonable cold air to south central Alaska on May 17 and 18th. In addition there was a weak low in the Gulf of Alaska that moved northward into Prince William Sound as the cold front approached.
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 cold front brought in unseasonable cold air to south central Alaska on May 17 and 18th. In addition there was a weak low in the Gulf of Alaska that moved northward into Prince William Sound as the cold front approached. The result was the front becoming stationary over the Anchorage area with over running moisture from the low that began as rain on Friday May 17th, but turned to snow through the course of the afternoon and persisted into Saturday morning.|This was an unusual event in the lateness of the storm in the season as it was the second latest date for accumulating snowfall in Anchorage on record. This storm also made the 2012-2013 snow season the longest duration one on record as there were 232 days (inclusive) between the first and last snowfalls of the season.|Although the official measurement of the Anchorage WFO was only .4 inches for the event, it was the anomaly. Snow reports around the rest of the Anchorage bowl ranged from 1.9 to 5.0 inches at lower elevations with numerous reports of 6 inches or more at elevations over 1000 ft.
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 May 17, 12:30 PM AKST, 1 hour 20 minutes earlier.
SOUTHCENTRAL AND SOUTHWEST ALASKA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ANCHORAGE AK 130 PM AKDT FRI MAY 17 2013 .ANALYSIS AND UPPER LEVELS... AN UPPER LEVEL TROUGH ACCOMPANIED BY MUCH-ADVERTISED UNSEASONABLY COLD AIR IS MOVING THROUGH SOUTHERN ALASKA THIS AFTERNOON. A WEAK LOW PRESSURE SYSTEM IN THE GULF HAS SPREAD WIDESPREAD PRECIPITATION ACROSS ALL OF SOUTHCENTRAL ALASKA...WHICH IS FALLING GENERALLY IN THE FORM OF RAIN AT LOWER ELEVATIONS AND SNOW AT HIGHER ELEVATIONS. SATELLITE IMAGERY SHOWS THE UPPER TROUGH BECOMING INCREASINGLY NEGATIVELY TILTED...WITH AN UPPER LEVEL LOW NEAR THE BERING STRAIT DROPPING INTO THE BASE OF THE TROUGH. FURTHER WEST...THE COLD FRONT HAS PASSED THROUGH MOST OF THE SOUTHWEST MAINLAND...CLEARING SKIES AND ALLOWING TEMPERATURES TO DROP INTO THE TEENS EARLIER THIS MORNING FROM THE KUSKOKWIM DELTA TO THE WESTERN KUSKOKWIM VALLEY. HIGH TEMPERATURES THIS AFTERNOON WILL STRUGGLE TO REACH THE UPPER 20S IN PARTS OF THE DELTA...WHERE THE AVERAGE HIGH THIS TIME OF YEAR SHOULD BE UPWARDS OF 50 DEGREES. WAY OUT WEST...HIGH PRESSURE REMAINS IN COMMAND OF THE BERING SEA REGION...THOUGH HIGH CLOUDS IN ADVANCE OF A NORTH PACIFIC LOW ARE APPROACHING THE FAR WESTERN ALEUTIANS. .MODEL DISCUSSION... MODEL AGREEMENT HAS CONTINUED TO IMPROVE TODAY WITH THE NAM JOINING THE OTHER SOLUTIONS IN THE TIMING AND EVOLUTION OF THE UPPER LEVEL TROUGH OVER THE MAINLAND TODAY (NAM HAD BEEN FASTER WITH SPEED OF THE UPPER TROUGH IN PREVIOUS DAYS). THUS CONFIDENCE HAS CONTINUED TO INCREASE THAT AN UNUSUAL LATE-SEASON SNOWFALL EVENT WILL BE UNFOLDING ACROSS SOUTHCENTRAL ALASKA TONIGHT AND CONTINUING THROUGH SATURDAY MORNING. THE NAM WAS THE PRIMARY MODEL USED TODAY...THOUGH NO STRONG PREFERENCES WERE NOTED AND NO MODELS WERE UNUSABLE. .SHORT TERM FORECAST... EAST OF THE ALASKA RANGE...COLD AIR IS SLOWLY BLEEDING INTO THE AREA BUT THIS TREND WILL ACCELERATE DRAMATICALLY BY LATE THIS AFTERNOON. AS THE ATMOSPHERIC COLUMN COOLS THE RAIN/SNOW MIX WILL TURN TO ALL SNOW EVEN AT LOWER ELEVATIONS. HIGHER ELEVATIONS WILL SEE THE MOST SNOWFALL...LIKELY APPROACHING 6 INCHES IN SOME LOCATIONS...WITH LOWER ELEVATIONS SIGNIFICANTLY LESS. AS SKIES CLEAR ON SATURDAY AFTERNOON TEMPERATURES SHOULD DROP SIGNIFICANTLY OVERNIGHT INTO SUNDAY MORNING. RECORD LOW TEMPERATURES IN ANCHORAGE ARE IN THE MID 20S...AND THESE RECORDS MAY BE THREATENED IF WINDS DIMINISH ENOUGH TO ALLOW SIGNIFICANT OVERNIGHT COOLING. EVEN IF THE RECORD LOWS ARE NOT REACHED...A WIDESPREAD HARD FREEZE IS EXPECTED ACROSS MUCH OF THE REGION FROM THE INLAND KENAI PENINSULA NORTHWARD. TEMPERATURES WILL START TO SLOWLY REBOUND ON SUNDAY AS HIGH PRESSURE MOVES IN FROM THE WEST. WEST OF THE ALASKA RANGE...BEHIND THE COLD FRONT TEMPERATURES DROPPED WELL BELOW FREEZING THIS MORNING AT MANY INLAND LOCATIONS OVER THE MAINLAND. MOSTLY CLEAR SKIES WILL ALLOW TEMPERATURES TO DROP AGAIN TONIGHT INTO THE LOWER TEENS...BEFORE A STEADY WARMING TREND ENSUES FOR THE LATTER HALF OF THE WEEKEND. HIGH PRESSURE CURRENTLY OVER THE BERING SEA WILL DRIFT EASTWARD...CONTINUING BENIGN CONDITIONS AND MOSTLY SUNNY SKIES. MARINE FOG/STRATUS OVER THE BERING AND ALEUTIANS WILL START TO SLOWLY DISSIPATE SATURDAY AS A GALE-FORCE FRONT APPROACHES THE WESTERN ALEUTIANS. THIS WEATHER FRONT AND ASSOCIATED RAIN SHIELD WILL MOVE TO THE EASTERN BERING BY LATE SUNDAY. .LONG TERM FORECAST... A MORE PROGRESSIVE WEATHER PATTERN WILL MOVE INTO THE REGION STARTING SUNDAY. THIS WILL SEE MOST AREAS RETURN TO NEAR-NORMAL TEMPERATURES BY THE MIDDLE OF NEXT WEEK...WITH RAIN MOVING INTO THE SOUTHWEST MAINLAND BUT SOUTHCENTRAL REMAINING MOSTLY DRY. .AER/ALU...WATCH/WARNING SUMMARY PUBLIC...SNOW ADVISORY 101 111 145 MARINE...GALE 130 132 150 172 175 176 FIRE WEATHER...NONE DIXON MAY 13
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1000 AM AKDT FRI MAY 17 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0930 AM SNOW 13 SE ANCHORAGE 61.08N 149.60W
05/17/2013 E0.0 INCH AK TRAINED SPOTTER
STEADY SNOWFALL WITH BIG SNOW FLAKES. SNOW IS MELTING ON
CONTACT WITH THE GROUND FORMING A SLUSHY LAYER ON HARD
SURFACES. SO FAR ONLY A TRACE OF SNOW HAS FALLEN.
VISIBILITY IS ONE HALF MILE OF LESS. REPORT IS NEAR THE
CHUGACH STATE PARK TRAILHEAD
&&
PETERSONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ANCHORAGE AK
1053 AM AKDT FRI MAY 17 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0700 AM SNOW 5 N HOMER 59.71N 151.52W
05/17/2013 M0.8 INCH AK OTHER FEDERAL
0.80 INCHES WET SNOW ACCUMULATION THIS MORNING ALONG
DIAMOND RIDGE AT ELEVATION 800 FT NORTH OF HOMER.
&&
ADIXON2 heavy snow. Local standard time, as filed.
Measured snowfall 3.5 inches in Southeast Anchorage at 700 ft elevation.|Measured snowfall 6.0 inches near Upper DeArmoun Rd at 1300 ft elevation. |Measured snowfall 6.3 inches mile 6.4 of Eagle River Rd.
Measured snowfall 4.4 inches near Eagle River.|Measured snowfall 5.0 inches in Chugiak.|Measured snowfall 9.1 inches on Upper Hiland Rd elevation 2165 ft.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Alaska in 2013Every state in 2013This day in weather historyWarnings in Alaska, May 2013
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: 450613, 450614.