A severe thunderstorm produced a wind gust to 58 mph at Akron Airport. A flash flood was also reported along St.
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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.
A severe thunderstorm produced a wind gust to 58 mph at Akron Airport. A flash flood was also reported along St. Louis Creek in Grand County. As a result, some of the streets in the town of Fraser were flooded.
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 Jul 5, 1:45 PM MST, 3 hours 15 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 245 PM MDT TUE JUL 5 2011 .SHORT TERM...CONVECTION HAS BROKEN OUT IN THE WARMER/DRIER AIR OVER THE MOUNTAINS...AND IS STEADILY SPREADING EAST. MEANWHILE RICHER LOW LEVEL MOISTURE...DEW POINTS AROUND 60...IS BEING ADVECTED WESTWARD WITH THE LEADING EDGE INTO MORGAN COUNTY. INITIAL CONVECTION WILL BE MOVING OFF THE FOOTHILLS INTO A LOW CAPE ENVIRONMENT...SO WE MAY NOT HAVE MUCH HAPPEN FOR THE NEXT COUPLE OF HOURS...BUT IT WILL ALL COME TOGETHER IN TIME. JET RELATED LIFT WILL STILL BE OVER THE AREA...SO ADDITIONAL FOOTHILLS CONVECTION IS LIKELY THROUGH EARLY EVENING AND WILL LIKELY GET STRONGER FOR A WHILE. THE FIRST STRONG CELLS MAY MOVE QUITE SLOWLY...ESPECIALLY WITH A LIKELY BOUNDARY COLLISION AS THE MOISTURE COMES IN. STILL EXPECTING SOME OUTFLOW BASED ORGANIZATION TO PUSH CONVECTION SLOWLY EASTWARD AFTER THAT. ADJUSTED POPS FOR TONIGHT UP A BIT...MAINLY OUT ON THE PLAINS. WEDNESDAY HAS SIMILAR THREATS...BETTER LOW LEVEL MOISTURE BUT DRYING ALOFT AND A BIT MORE WIND ALOFT. SHOULD ADD UP TO A BIT LOWER FLASH FLOOD THREAT AND A BIT HIGHER SEVERE THREAT...BUT BOTH WILL STILL BE THERE. THE COMBINATION OF HIGHER MOISTURE CONTENT AND A DEEPER WARM CLOUD LAYER MAY MAKE UP FOR THE FASTER STORM MOTION TO PRODUCE HEAVY RAIN AGAIN. TEMPERATURES WILL BE COOLER...BUT WITH THE HIGH DEW POINTS CONVECTIVE TEMPS WILL ONLY BE IN THE 70S. .LONG TERM...FOR WEDNESDAY NIGHT...A MOIST AND UNSTABLE AMS WILL REMAIN IN PLACE THROUGH THE EVENING. GOOD AFTN INSTBY WITH CAPES 1100-1300 J/KG...PRECIPTABLE WATER VALUES 1.3-1.5 INCHES AND STORM MOTIONS LESS THAN 10 KTS WILL ALLOW FOR WET MICROBURSTS AND POSSIBLE FLASH FLOODING ISSUES. WL KEEP CHC TSTMS GOING FROM THE URBAN CORRIDOR WESTWARD...WITH LIKELY POPS OVER THE NORTHEAST PLAINS. THE FLOW ALOFT WILL REMAIN WEAK THROUGH THE REST OF THE PERIOD IT WILL JUST BE A QUESTION OF HOW MUCH MOISTURE WILL BE AROUND FOR AFTN AND EVENING THUNDERSTORMS. THE UPPER RIDGE WILL BE CENTERED OVER THE DESERT SOUTHWEST THROUGH SATURDAY THEN ITS SHIFT OVER THE SRN PLAINS/MISSISSIPPI VALLEYS BY EARLY NEXT WEEK. AS IT DOES THE WEAK FLOW ALOFT WILL SHIFT FM WEST/NORTHWESTERLY TO SOUTHWESTERLY WHICH IS THE MORE TYPICAL FLOW ALOFT FOR THE SUMMER MONSOON. WL GO WITH CHC POPS EACH DAY FM THE URBAN CORRIDOR WESTWARD WITH SLGT CHC POPS ACROSS THE NORTHEAST PLAINS. && .AVIATION...THUNDERSTORM ACTIVITY WILL INCREASE WITH THE MAIN ACTIVITY IN THE DENVER AREA DURING THE LATE AFTERNOON INTO THE EARLY EVENING. EXPECT PERIODS WHERE INSTRUMENT APPROACHES TO KDEN WILL BE NEEDED...AND THERE WILL BE LOCALIZED IFR VISIBILITIES IN AREAS OF HEAVY RAIN. AFTER THE STORMS DEPART...MVFR CEILINGS ARE EXPECTED TO PREVAIL LATE TONIGHT INTO EARLY WEDNESDAY MORNING. ANOTHER ROUND OF THUNDERSTORMS WEDNESDAY AFTERNOON WITH PERIODS OF INSTRUMENT APPROACHES TO KDEN AND LOCALIZED IFR IN HEAVY RAIN. && .HYDROLOGY...THUNDERSTORMS ACROSS THE AREA THREATEN HEAVY RAIN OF 1 TO 2 INCHES IN AN HOUR WHICH COULD CAUSE FLASH FLOODING IN SUSCEPTIBLE AREAS. HEAVIER RAIN IS POSSIBLE IN RICHER MOISTURE ON THE PLAINS. CELL MOTION OF 10 TO 15 KNOTS IS EXPECTED...THOUGH THERE COULD BE SOME SLOWER MOTIONS IN THE LATE AFTERNOON FROM CONVERGENT WINDS...MOST LIKELY JUST EAST OF THE MOUNTAINS. HEAVIER RAIN IS ALSO POSSIBLE ON THE PLAINS OVERNIGHT FROM TRAINING OF CELLS OVER THE SAME AREA. THIS COULD PRODUCE 4 INCHES OF RAIN OVER A COUPLE OF HOURS. THUNDERSTORMS WEDNESDAY AFTERNOON AND EVENING WILL BRING ANOTHER THREAT OF FLASH FLOODING FROM THE FOOTHILLS EASTWARD. THE ENVIRONMENT WILL HAVE MORE MOISTURE BUT STORMS WILL BE MOVING MORE QUICKLY. CURRENT RIVER AND STREAM FLOWS HAVE TRENDED SLIGHTLY LOWER IN THE LAST 24 HOURS. THIS TREND WILL CONTINUE AS TEMPERATURES COOL AND SNOWMELT RATES DECREASE. HOWEVER...LOCALLY HEAVY RAINFALL MAY ADD TO RUNOFF ISSUES TONIGHT INTO WEDNESDAY WITH POTENTIAL FOR RISES ON LARGER STREAMS. WATCHING SEVERAL CREEKS WITH HIGH SNOW MELT RUNOFF THAT WOULD NOT BE ABLE TO TAKE MUCH MORE WATER. FLOOD ADVISORIES... BIG THOMPSON RIVER THROUGH ESTES PARK UNTIL NOON WEDNESDAY. COLORADO RIVER NEAR KREMMLING UNTIL LATE WEDNESDAY AFTERNOON. && .BOU WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 6 PM MDT THIS EVENING THROUGH LATE TONIGHT FOR COZ048>051. FLASH FLOOD WATCH UNTIL 10 PM MDT THIS EVENING FOR COZ035-036-038>045. && GIMMESTAD/COOPER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1124 AM MDT TUE JUL 05 2011 COZ030>051-061200- 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- 1124 AM MDT TUE JUL 05 2011 ...THUNDERSTORMS WITH HEAVY RAIN AND POSSIBLE FLOODING THIS AFTERNOON AND TONIGHT... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS WILL DEVELOP IN AND NEAR THE FOOTHILLS THIS AFTERNOON. THE THUNDERSTORMS WILL INCREASE AS THEY MOVE SLOWLY EAST ACROSS THE PLAINS TONIGHT. THE MAIN THREATS FROM THE STORMS WILL BE FLASH FLOODING AND LARGE HAIL UP TO GOLF BALL SIZE. THERE IS A SMALLER THREAT OF DAMAGING WINDS AND TORNADOES. STORMS TODAY WILL PRODUCE RAINFALL RATES OF UP TO 2 INCHES IN AN HOUR. THERE IS POTENTIAL TODAY FOR MULTIPLE STORMS TO MOVE OVER THE SAME AREA...WHICH COULD RESULT IN UP TO 4 INCHES OF RAIN OVER SEVERAL HOURS. THE THREAT OF BOTH FLASH FLOODING AND SEVERE WEATHER APPEARS GREATEST IN AREAS ALONG AND NORTH OF INTERSTATE 76...WITH THE FLOOD THREAT ALSO ENHANCED IN BURN AREAS AND URBAN AREAS. A MORE MOIST AND UNSTABLE ENVIRONMENT IN THE WAKE OF A WEAK COLD FRONT WILL BRING THE THREAT OF SEVERE WEATHER AND HEAVY RAINFALL. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY ON WEDNESDAY...SCATTERED TO NUMEROUS THUNDERSTORMS WILL AGAIN BE EXPECTED. THE STORMS WILL BE BE SLOW MOVING...POTENTIALLY SEVERE AND PRODUCE HEAVY RAINFALL. MOISTURE WILL DECREASE FOR THURSDAY THROUGH MONDAY. HOWEVER THE OVERALL WEATHER PATTERN WILL ALLOW DAILY ISOLATED TO SCATTERED THUNDERSTORMS IN THE AFTERNOON AND EVENINGS... ALTHOUGH A FEW MAY CONTINUE INTO EARLY MORNING HOURS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL BE NEEDED AFTER 1 PM. GIMMESTAD/COOPER
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 541 PM MDT TUE JUL 5 2011 COZ043-060015- CENTRAL AND SOUTH WELD COUNTY CO- 541 PM MDT TUE JUL 5 2011 THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL WELD COUNTY AT 541 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND WIND GUSTS TO AROUND 40 MPH. THIS STORM WAS LOCATED 4 MILES SOUTHEAST OF PROSPECT VALLEY...OR 33 MILES SOUTHEAST OF GREELEY...MOVING EAST AT 10 MPH. LOCATIONS IN THE ADVISORY INCLUDE BUT ARE NOT LIMITED TO ROGGEN AND PROSPECT VALLEY. PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS STORM WILL PRODUCE DANGEROUS CLOUD-TO-GROUND LIGHTNING. IF OUTDOORS...STAY AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES AND MOVE INDOORS IF POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID USING LAND LINE TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE IN DANGER OF BEING STRUCK BY LIGHTNING. && LAT...LON 4025 10416 4001 10417 4001 10441 4025 10444 TIME...MOT...LOC 2341Z 257DEG 11KT 4005 10432
The Denver radar (KFTG), 107 km away, was scanning. The volume nearest the first event began at 00:01 UTC.
1 flash flood, 1 thunderstorm wind. Local standard time, as filed.
The combination of heavy rain and spring runoff caused flash flooding along St. Louis Creek.
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, July 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: 338786, 319452.