An unseasonably strong low pressure system moved across the Great Basin and produced high wind and dust over northern Arizona.
Every event with a place to put it; 13 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 FGZ wrote it up.
An unseasonably strong low pressure system moved across the Great Basin and produced high wind and dust over northern Arizona.
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 Flagstaff, AZ wrote its last area forecast discussion before the first event at May 28, 9:15 PM MST, 2 hours 15 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FLAGSTAFF AZ 915 PM MST SAT MAY 28 2011 .SYNOPSIS...AN UNSEASONABLY STRONG LOW PRESSURE SYSTEM WILL MOVE OVER NEVADA ON SUNDAY. THE MAIN IMPACT FROM THIS SYSTEM WILL BE VERY STRONG WINDS AND BLOWING DUST ON SUNDAY. THERE WILL BE A SLIGHT CHANCE OF SHOWERS FROM LATE SUNDAY INTO EARLY MONDAY ALONG WITH COOLER TEMPERATURES. EXPECT A WARMING TREND TUESDAY THROUGH THURSDAY. && .DISCUSSION...THOUGH WINDS ARE TAPERING OFF SOMEWHAT FOR MOST LOCATIONS TONIGHT...THE WINDIEST CONDITIONS OF THE SEASON ARE LIKELY FOR TOMORROW. DANGEROUS BLOWING DUST WILL LIKELY REDUCE VISIBILITIES TO HAZARDOUS LEVELS ACROSS PORTIONS OF THE NORTHLAND...ESPECIALLY EAST OF FLAGSTAFF AND NEAR THE FOUR CORNERS. PLEASE PLAN ACCORDINGLY WHEN MAKING HOLIDAY TRAVEL DECISIONS. && .PREV DISCUSSION /330 PM MST/...SURFACE WINDS WILL DECREASE SOME THIS EVENING...BUT WILL REMAIN BREEZY. SOME PASSES AND LOCATIONS NORTHEAST OF HIGHER TERRAIN WILL REMAIN WINDY TONIGHT. THE LOW PRESSURE CENTER WILL MOVE OVER WESTERN NEVADA BY SUNDAY MORNING INCREASING THE WINDS OVER ARIZONA. FORECAST SOUNDINGS INDICATE THAT FREE AIR WINDS AS HIGH AS 50KTS (58 MPH) WILL LOWER TO AROUND 8500 MSL OVERNIGHT TONIGHT AND INTO SUNDAY MORNING. THIS MEANS EVEN STRONGER SURFACE WINDS ARE IN STORE FOR SUNDAY. SUNDAY NIGHT...THE COLD FRONT WILL MOVE ACROSS THE AREA AND ISOLATED TO SCATTERED SHOWERS WILL DEVELOP MAINLY ALONG THE NRN BORDER REGION AND POSSIBLY AS FAR SOUTH AS THE MOGOLLON RIM. ONLY LIGHT AMOUNTS OF RAIN AND HIGH ELEVATION SNOW IS EXPECTED. SNOW LEVELS WILL BRIEFLY FALL AS LOW AS 7000 TO 7500 FEET BY LATE SUNDAY AND EARLY MONDAY ACROSS NRN AZ. WIND SHELTERED AREAS COULD FALL LOWS INTO THE UPPER 20S AND LOWER 30S AT ELEVATIONS ABOVE 7000 FEET WITH TEMPS IN THE UPPER 30S TO MID 40S ELSEWHERE. BY MID WEEK...SUBSTANTIAL RIDGING WILL DEVELOP ACROSS THE SOUTHERN PLAINS AND NRN MEXICO. A STRONG LOW WILL DEVELOP OVER THE PACIFIC NORTHWEST. THIS WILL ALLOW TEMPERATURES TO RETURN TO SEASONABLE LEVELS. AS THE RIDGE DEVELOPS...SUBTROPICAL MOISTURE FROM THE GULF OF MEXICO WILL PUSH NORTHWESTWARD ACROSS NEW MEXICO AND INTO EASTERN AZ BRINGING A SLIGHT CHANCE OF SHOWERS...THUNDERSTORMS...AND DRY LIGHTNING. ELSEWHERE...IT WILL REMAIN MOSTLY CLEAR...DRY...WITH DAILY SOUTHWEST WINDS. && .AVIATION...FOR THE 06Z PACKAGE...VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24 HOURS. WINDS WILL DECREASE TO 10-20 KT WITH GUSTS TO 30 KT MOST AREAS OVERNIGHT. HOWEVER...LOCALLY STRONG WINDS GUSTING IN EXCESS OF 40 KT ARE POSSIBLE EAST OF HIGHER TERRAIN FEATURES SUCH AS THE SAN FRANCISCO PEAKS AND KAIBAB PLATEAU. ON SUNDAY...SOUTHWEST WINDS OF 25-35 KT WITH GUSTS OF 45-55 KT ARE ANTICIPATED. AREAS OF BLOWING DUST MAY DEVELOP ACROSS NE ARIZONA...WITH VSBY BELOW 1SM OVER SOME AREAS. A FEW SHOWERS ARE ALSO POSSIBLE NORTH OF A KGCN-KRQE LINE AFTER 22Z SUNDAY. AVIATION DISCUSSION NOT UPDATED FOR AMENDMENTS. && .FIRE WEATHER...BREEZY WINDS WILL CONTINUE OVERNIGHT WITH POOR RH RECOVERY. ON SUNDAY...EXPECT VERY STRONG WINDS WITH WIND GUSTS EXCEEDING 50 MPH AT TIMES...ESPECIALLY FROM THE MOGOLLON RIM NORTHWARD. IN ADDITION...RH VALUES AT MANY LOWER ELEVATION LOCATIONS WILL DROP TO BELOW 15 PERCENT SUNDAY AFTERNOON. AS A RESULT...A RED FLAG WARNING IS IN EFFECT DURING THE DAY SUNDAY FOR PORTIONS OF NORTHERN ARIZONA...PRIMARILY BELOW 6000 FEET. SUNDAY NIGHT...THE UPPER LOW WILL CROSS THE STATE...BRINGING A SLIGHT CHANCE OF SHOWERS TO THE HIGHER TERRAIN NORTH OF INTERSTATE 40. LOW PRESSURE WILL MOVE TO THE EAST ON MONDAY LEAVING BEHIND BELOW NORMAL TEMPERATURES AND MUCH LIGHTER WINDS. TUESDAY THROUGH THURSDAY...HIGH PRESSURE WILL BUILD OVER TEXAS WHILE LOW PRESSURE DEVELOPS OFF THE WEST COAST. THE IMPACTS OF THIS PATTERN SHIFT WILL BE INCREASING DAYTIME TEMPERATURES... STRENGTHENING SOUTHWEST WINDS AND LOWERING RELATIVE HUMIDITY VALUES. ENOUGH MID-LEVEL MOISTURE COULD MOVE IN BY WEDNESDAY AND THURSDAY FOR A SLIGHT CHANCE OF SHOWERS OVER THE WHITE MOUNTAINS. && .FGZ WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 6 AM TO 9 PM MST SUNDAY FOR AZZ004>007-009>017-039-040. RED FLAG WARNING FROM 11 AM TO 7 PM MST SUNDAY FOR AZ FIRE WX ZONES 105-109>114-118-137>140. WIND ADVISORY FROM 6 AM TO 9 PM MST SUNDAY FOR AZZ008-018-037- 038. && PUBLIC.....................KD/MAS AVIATION/FIRE WX...........JJ FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT WEATHER.GOV/FLAGSTAFF.
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE FLAGSTAFF AZ 840 PM MST SAT MAY 28 2011 AZZ004>018-037>040-291315- KAIBAB PLATEAU-MARBLE AND GLEN CANYONS-GRAND CANYON COUNTRY- COCONINO PLATEAU-YAVAPAI COUNTY MOUNTAINS- NORTHEAST PLATEAUS AND MESAS HWY 264 NORTHWARD-CHINLE VALLEY- CHUSKA MOUNTAINS AND DEFIANCE PLATEAU- LITTLE COLORADO RIVER VALLEY IN COCONINO COUNTY- LITTLE COLORADO RIVER VALLEY IN NAVAJO COUNTY- LITTLE COLORADO RIVER VALLEY IN APACHE COUNTY- WESTERN MOGOLLON RIM-EASTERN MOGOLLON RIM-WHITE MOUNTAINS- NORTHERN GILA COUNTY-YAVAPAI COUNTY VALLEYS AND BASINS- OAK CREEK AND SYCAMORE CANYONS-BLACK MESA AREA- NORTHEAST PLATEAUS AND MESAS SOUTH OF HWY 264- 840 PM MST SAT MAY 28 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL ARIZONA...NORTH CENTRAL ARIZONA...NORTHEAST ARIZONA AND WEST CENTRAL ARIZONA. .DAY ONE...THIS AFTERNOON AND TONIGHT AN UNSEASONABLY STRONG PACIFIC STORM SYSTEM WILL MOVE ACROSS THE SOUTHWEST TODAY THROUGH MONDAY. THE MAIN IMPACT WILL BE STRONG WINDS AND CRITICAL FIRE WEATHER CONDITIONS...PREDOMINANTLY DURING THE DAYLIGHT HOURS. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY FOR SUNDAY...A HIGH WIND WARNING IS IN EFFECT FOR SOUTHWEST WINDS OF 30 TO 40 MPH WITH GUSTS OF 50 TO 60 MPH OR HIGHER. WINDS THIS STRONG MAY PRODUCE SUBSTANTIAL AREAS OF BLOWING DUST AND REDUCED VISIBILITIES RESULTING IN TEMPORARY CLOSURES OF HIGHWAYS ACROSS EASTERN ARIZONA...INCLUDING INTERSTATE 40 FROM EAST OF FLAGSTAFF TO THE NEW MEXICO BORDER. CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED AGAIN ON SUNDAY... PRIMARILY FOR ELEVATIONS BELOW 6000 FEET...THUS A RED FLAG WARNING HAS BEEN ISSUED. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
The national radar mosaic for the moment the first event began.
12 high wind, 1 dust storm. Local standard time, as filed.
The RAWS at House Rock reported wind gusts in excess of 60 MPH for several hours during the night.
The ASOS at Winslow measured wind gusts 58 MPH or higher for about half an hour. The peak wind gust was 63 MPH.
A weather station in Doney Park measured wind gusts to 58 MPH or higher between 11:25 and 11:32 AM and again between 2:50 and 3:00 PM. The peak wind gust was 60 MPH. The peak wind gust at the Flagstaff Airport was 64 MPH.
The ADOT weather station at Two Guns reported wind gusts of 58 MPH or higher from late morning into early evening. The peak wind gust was 58 MPH. Blowing dust dropped the visibility at times...down to 5 miles around 1:00 PM.
The RAWS at Limestone Canyon reported high wind gusts from about noon to 9 PM MST.|A spotter in Linden reported a peak wind gust of 59 MPH.
The Window Rock ASOS reported wind gusts of 58 MPH or higher from about 1250 PM to 110 PM. The peak wind gust was 60 MPH. The ADOT wind sensor at Lupton reported wind gusts of 58 MPH or higher off and on from about 1:30 PM to 6:10 PM. The peak wind gust was also 60 MPH.
The Petrified Forest National Park reported a peak wind gust of 62 MPH. A wind gust to 60 MPH was reported in Kykotsmovi Village.
The Grand Canyon ASOS reported peak winds of 58 MPH.
The Petrified Forest National Park reported a peak wind gust of 62 MPH.
The Hopi RAWS reported sustained winds of 41 MPH with peak wind gusts of 60 MPH.
The visibility was down to 25 feet in blowing dust at times in the community of Many Farms.
A trained spotter just east of Chinle estimated wind gusts to be 65 MPH.
The Show Low Airport reported high wind gusts for several hours during the evening.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2011Every state in 2011This day in weather historyWarnings in Arizona, May 2011
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: 312015, 315748, 315729, 315834, 312017, 315779, 315810, 315824, 315813, 315919, 315846, 315923, 312020.