Strong southwest winds blew a semi-truck on its side over Interstate 76, between Wiggins and Fort Morgan. In addition, a small section of power lines were blown down and an 80-ft metal shed was partially toppled near Fort Morgan.
Every event with a place to put it; 1 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 BOU wrote it up.
Strong southwest winds blew a semi-truck on its side over Interstate 76, between Wiggins and Fort Morgan. In addition, a small section of power lines were blown down and an 80-ft metal shed was partially toppled near Fort Morgan.
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 Denver/Boulder, CO wrote its last area forecast discussion before the first event at Apr 9, 2:50 PM MST, 1 hour 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 350 PM MDT SAT APR 09 2011 .SHORT TERM...PRECIPITATION BEGINNING TO DEVELOP ACROSS MOUNTAINS AS INSTABILITY AND QG ASCENT INCREASES AHEAD OF APPROACHING UPPER TROUGH. ACROSS PLAINS...GUSTY SOUTHERLY WINDS NOTED ACROSS MUCH OF THE AREA...WITH SOUTHEAST WINDS ACROSS EASTERLY LARIMER COUNTY. HUMIDITY READINGS HAVE FALLEN INTO THE TEENS MOST LOCALS. WILL KEEP THE RED FLAG WARNING GOING THROUGH 9 PM MDT. TROUGH TO MOVE ACROSS CFWA TONIGHT WITH MOISTURE SPREADING ACROSS MOUNTAINS ONTO PLAINS DURING THE EVENING. PRECIPITATION TO SPREAD ACROSS MOUNTAINS ONTO PLAINS AS FRONT MOVES ACROSS REGION. SOME LIGHTNING RECENTLY NOTED IN WESTERN COLORADO...INDICATING THAT TROUGH IS FAIRLY UNSTABLE. WILL ADD A SLIGHT CHANCE OF THUNDER TO THE MOUNTAIN ZONES THIS EVENING. SOUTHWEST FLOW ALOFT INITIALLY NOT FAVORABLE FOR OROGRAPHICS THIS EVENING...WILL KEEP AMOUNTS ON THE LIGHT SIDE... THOUGH THE CONVECTION COULD ADD A FEW MORE INCHES. BETTER OROGRAPHIC SNOW OCCURS AFTER MIDNIGHT AS FLOW SHIFTS TO WESTERLY. ACROSS PLAINS...FRONT TO MOVE ACROSS AREA AFTER 03Z...AS NOTED BY THE MODELS. WIND FIELDS SHOW FLOW WESTERLY BEHIND FRONT...THEN NORTHWEST AFTER 06Z. THIS DOWNSLOPE DOESN'T BODE WELL FOR PRECIPITATION ACROSS FOOTHILLS AND ADJACENT PLAINS. DID UP POPS TO LIKELY FOR THE FOOTHILLS TONIGHT GIVEN THE THE QG ASCENT. AS FOR PLAINS...KEPT THE CHANCE POPS FOR MOST OF THE PLAINS TONIGHT...WITH THE LIKELY POPS NEAR THE WYOMING BORDER. TEMPERATURES TONIGHT...BASED ON FORECAST SOUNDINGS...SHOW TEMPERATURES MAINLY ABOVE FREEZING. SO THE MIXTURE OF RAIN AND SNOW STILL LOOKS GOOD WITH MAINLY RAIN FURTHER EAST. ON SUNDAY...FLOW ALOFT SHIFTS TO THE NORTHWEST AS TROUGH MOVES ONTO PLAINS. STRONG QG DESCENT MOVES INTO MOUNTAINS BY 18Z AND ACROSS PLAINS DURING THE AFTERNOON. DESPITE THE GOOD MOUNTAIN OROGRAPHICS THE DOWNWARD MOTION SHOULD DECREASE THE SNOW CHANCES. WILL DECREASE THE MOUNTAIN POPS TO LIKELY DURING THE AFTERNOON. IN ALL SNOW AMOUNTS SHOULD STAY BELOW ADVISORY CRITERIA. AS FOR PLAINS... STRONG DOWNSLOPE FLOW WILL LIMIT PRECIP CHANCES. THE CHANCE POPS LOOK REASONABLE. THE LIKELY POPS STILL LOOK REASONABLE AWAY FROM THE DOWNSLOPE. GUIDANCE SHOWS HIGHS ACROSS PLAINS IN THE 50S WHICH LOOKS ON TRACK. CURRENT TEMPERATURE GRIDS IN LINE WITH GUIDANCE...WILL CHANGE LITTLE. .LONG TERM...IMPROVEMENT CONTINUES SUNDAY NIGHT WITH SUBSIDENCE AND DRYING ON BACKSIDE OF EXITING MID-LEVEL TROUGH. MODELS HOWEVER STILL INDICATE LIGHT QPF OVER FAR EASTERN ZONES AND HIGHER ELEVATIONS IN THE EVENING. 30-40 PCT POPS FOR MTN ZONES AND 10-20 PCT POPS ON THE PLAINS STILL LOOK GOOD. BY MONDAY MORNING DRYING WELL UNDERWAY WITH DEEP NWLY FLOW. COULD SEE GUSTY NWLY SFC WINDS OF 15-30KT ON THE HIGH MTN RIDGES AND ACROSS THE NERN CORNER OF THE STATE DURING THE MORNING. GENERAL MODEL CONSENSUS SHOWS THE 500MB RIDGE AXIS PASSING OVER ERN COLORADO IN THE AFTERNOON COINCIDING WITH LIGHTER WINDS BOTH SFC AND ALOFT. MAX TEMPS ON MONDAY ABOUT 2-3C ABOVE AVERAGE FOR THE DATE. WARM UP CONTINUES TUESDAY WITH THE UPPER RIDGE WELL EAST OF THE STATE AND SWLY FLOW STRENGTHENING ALOFT. BNDRY LAYER EAST OF THE MTNS LOOKS DRY BOTH MONDAY AND TUESDAY BUT NOT AS DRY AS THE PAST COUPLE OF DAYS...HOWEVER SHOULD SEE RESUMPTION OF GUSTY SLY FLOW ON THE PLAINS ROUGHLY EAST OF THE SFC TROUGH. BY LATE IN THE DAY MODEL RH FIELDS SHOW INCREASING MID AND HIGH LEVEL MOISTURE ACROSS THE NWRN QUADRANT OF COLORADO AS MODELS SHOW WEAK QG ASCENT ASSOCIATED WITH LIFT GENERATED BY A NEARBY JET. LAPSE RATES LATE IN THE DAY MAY BECOME STEEP ENOUGH TO PRODUCE A FEW LIGHTNING STROKES FROM SHOWERS OVER HIGHER ELEVATIONS ROUGHLY NORTH OF I-70. TUESDAY NIGHT MODELS FOR THE MOST PART SHOW A FLAT SHORTWAVE TROUGH OUT WEST OVER UTAH SWEEPING ACROSS COLORRADO GIVING THE HIGH COUNTRY ANOTHER CHANCE OF SNOW AND A SLIGHT CHANCE OF RAIN SHOWERS AT LOWER ELEVATIONS. WAVE LIFTS NEWRD OVER NEBRASKA ON WEDNESDAY MORNING PUTTING NERN COLORADO UNDER SWATH OF WARM DRY MID-LEVEL AIR. HOWEVER AT THE SFC MODELS SHOW A SFC LOW SPINNING OVER W/NWRN KANSAS AND NLY WINDS SPILLING DOWN OUT OF WY/NEB. THE STG STABILITY PRODUCED BY THE COMBINATION OF COOL AIR AT THE SFC AND WARMER AIR ALOFT IN THE MORNING IS REPLACED BY MUCH STEEPER LAPSE RATES IN THE AFTERNOON AND EVENING AS TEMPS COOL ALOFT WITH THE APPROACH OF ANOTHER SHORTWAVE TROUGH. MODELS SHOW A FAIR AMOUNT OF QPF AROUND LATE IN THE DAY WEDNESDAY AND OVERNIGHT WITH SNOW LEVEL LOWERING TO AROUND 9000-9500 FT MSL BY NIGHTFALL. HOWEVER ANY SNOW ACCUMULATION...WHICH REMAINS TO BE DETERMINED...SHOULD REMAIN CONFINED TO HIGHER ELEVATIONS WEST OF THE CONTINENTAL DIVIDE. SOUNDS LIKE A BROKEN RECORD...DOESN/T IT? LOW CAPES AND STEEP SFC-600MB LAPSE RATES MAY ALSO SPAWN A FEW LATE DAY WEAK T-STORMS ON THE PLAINS...MAINLY SOUTH OF I-76. TROUGH AND ACCOMPANYING WEATHER LOOKS AS THOUGH IT WILL MOVE OUT SLOWLY ON THURSDAY LEAVING DRIER AND WARMER WEATHER CONDITIONS FOR FRIDAY AND BEYOND. && .AVIATION...GUSTY SOUTHERLY WINDS HAVE MIXED ACROSS THE AREA AIRPORTS...WITH SOME GUSTS TO 35 KTS. THE WINDS SHOULD DECREASE BY 03Z AND TURN WEST TO NORTHWEST WITH THE PASSAGE OF A FRONT LATE THIS EVENING. THE WINDS WILL REMAIN NORTHWEST THROUGH THE DAY SUNDAY... WITH SPEEDS IN THE 15 TO 25 KT RANGE. RAIN SHOWERS TO DEVELOP THIS EVENING AS THE FRONT MOVES ACROSS AREA. CEILINGS OF 3000-5000 FOOT CEILINGS COULD DEVELOP OVERNIGHT. THERE MAY BE SOME SNOW MIXED IN WITH THE RAIN...BUT NO ACCUMULATIONS ARE EXPECTED AT THE DENVER AREA AIRPORTS. RAIN SHOWERS WILL BE POSSIBLE THROUGH THE DAY SUNDAY THOUGH CEILINGS WILL STAY ABOVE 7000 FEET AGL. && .BOU WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ214-216-239>251. && D-L/BAKER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1142 AM MDT SAT APR 09 2011 COZ030>051-101200- JACKSON COUNTY BELOW 9000 FEET-WEST JACKSON AND WEST GRAND COUNTIES ABOVE 9000 FEET-GRAND AND SUMMIT COUNTIES BELOW 9000 FEET-SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/ NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET-SOUTH AND SOUTHEAST GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/GILPIN/CLEAR CREEK/ SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE 9000 FEET-LARIMER AND BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET-JEFFERSON AND WEST DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK COUNTIES BELOW 9000 FEET-CENTRAL AND SOUTHEAST PARK COUNTY-LARIMER COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY-BOULDER AND JEFFERSON COUNTIES BELOW 6000 FEET/WEST BROOMFIELD COUNTY-NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/ EAST BROOMFIELD COUNTY-ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET-NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD COUNTY-MORGAN COUNTY-CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES- NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN COUNTY-SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN COUNTY-LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS COUNTY- 1142 AM MDT SAT APR 09 2011 ...RED FLAG WARNING FOR THE SOUTHERN FOOTHILLS...PALMER DIVIDE AND OVER THE PLAINS ALONG AND SOUTH OF A LINE FROM DENVER TO AKRON THIS AFTERNOON AND EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SOUTH TO SOUTHWEST WINDS OF 20 TO 30 MPH SPREAD ACROSS THE PLAINS THIS AFTERNOON AHEAD OF A COLD FRONT. SOME GUSTS IN THE 40 TO 50 MPH RANGE CAN BE EXPECTED IN AREAS ALONG AND SOUTH OF INTERSTATE 76. THE WINDS WILL COMBINE WITH WARM TEMPERATURES AND LOW HUMIDITIES TO PRODUCE EXTREME FIRE DANGER. THE COLD FRONT WILL MOVE THROUGH THE REGION TONIGHT...WITH SNOW SHOWERS DEVELOPING IN THE MOUNTAINS SNOW ACCUMULATIONS IN THE HIGH COUNTRY WILL RANGE FROM 2 TO 6 INCHES. ACROSS THE PLAINS...THERE WILL BE A CHANCE OF RAIN SHOWERS...MIXED AT TIMES WITH SNOW. RAINFALL AMOUNTS WILL GENERALLY BE LIGHT...WITH NO SNOW ACCUMULATION. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SNOW SHOWERS IN THE MOUNTAINS AND HIGH VALLEYS WILL GRADUALLY DECREASE IN COVERAGE AND INTENSITY THROUGH THE DAY SUNDAY WITH ONLY LIGHT ADDITIONAL ACCUMULATION ON THE HIGHER WEST AND NORTHWEST FACING MOUNTAIN SLOPES. ON THE PLAINS...RAIN AND SNOW SHOWERS SUNDAY MORNING SHOULD MOVE EAST OF THE AREA BY LATE IN THE DAY. LOWER ELEVATIONS GENERALLY EAST OF A BRIGGSDALE TO ELBERT LINE COULD SEE SOME LIGHT SNOW ACCUMULATION IN THE MORNING. THEN LOOK FOR A RETURN TO WARMER AND DRIER CONDITIONS ON MONDAY AND TUESDAY...ONLY TO RETURN TO COOLER AND UNSETTLED WEATHER ON WEDNESDAY AND THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. D-L/BAKER
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2011Every state in 2011This day in weather historyWarnings in Colorado, April 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: 302491.