Very intense thunderstorm winds damaged trees and power lines in addition to a building under construction near Iliff. One tornado touched down in an open field as well.
Every event with a place to put it. 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.
Very intense thunderstorm winds damaged trees and power lines in addition to a building under construction near Iliff. One tornado touched down in an open field as well.
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 18, 1:42 PM MST, 2 hours 56 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER CO 242 PM MDT SUN JUL 18 2010 .SHORT TERM...THE UPPER HIGH OVER ARIZONA WILL SLIDE SLOWLY EASTWARD IN THE NEXT 24 HOURS. WESTERLY FLOW ALOFT WILL CONTINUE OVER COLORADO. WEAK UPPER DISTURBANCES HIDDEN IN THE FLOW IN COMBINATION WITH MOISTURE UNDER THE RIDGE WILL ALLOW DAILY THUNDERSTORMS TO DEVELOP TODAY AND TO A LESSER EXTEND MONDAY. THUNDERSTORMS HAVE BEEN RAPIDLY PROLIFERATING OVER THE FOOTHILLS FROM SOUTHERN COLORADO TO SOUTHERN WYOMING. THERE WILL A CHANCE OF SEVERE WEATHER IN THE NORTHEAST CORNER OF COLORADO THIS EVENING...AS DEWPOINTS ABOVE 60 DEGREES PERSIST THERE. ELSEWHERE WITH GOOD STORM MOVEMENT...HIGH CLOUD BASES WILL GET GUSTY OUTFLOW WINDS...AND ONLY A SHORT BURST OF RAIN. ONLY MINOR ADJUSTMENTS TO PREVIOUS FORECAST. .LONG TERM...MODELS HAVE THE UPPER RIDGE CENTER SOUTH OF COLORADO MONDAY NIGHT WITH WESTERLY FLOW ALOFT. ON TUESDAY AND TUESDAY NIGHT...THE UPPER RIDGE CENTER SHIFTS EASTWARD WITH THE FLOW ALOFT BECOMING MORE WEST-SOUTHWESTERLY BY LATE TUESDAY. ON WEDNESDAY...THE UPPER RIDGE STAYS WELL EAST-SOUTHEAST OF COLORADO WITH SOUTHWESTERLY FLOW ALOFT FOR THE CWA. WEAK UPPER TROUGHING IS INDICATED TO OUR NORTH THROUGH MOST OF THE PERIODS. THE SYNOPTIC SCALE ENERGY PROGGS CONTINUE TO INDICATE BENIGN ENERGY THROUGH THE PERIODS. THE BOUNDARY LAYER WIND PROGGS CONTINUE TO SHOW AN UPSLOPE COMPONENT TO THE WINDS LATER MONDAY NIGHT THROUGH WEDNESDAY. THERE IS A WEAK SURGE OF COOLER...MORE MOIST AIR TO MOVE ACROSS THE PLAINS MONDAY NIGHT/TUESDAY MORNING...THEN STAY AROUND FOR WEDNESDAY. FOR MOISTURE...IT INCREASES AT MOST LEVELS AND CONTINUES PRETTY MOIST THROUGH WEDNESDAY. MODELS HAVE BOUNDARY LAYER DEW POINTS INCREASING FROM EAST TO WEST MONDAY NIGHT. FOR TUESDAY THROUGH WEDNESDAY NIGHT ...DEW POINT READINGS ARE PROGGED IN THE 60S FOR THE PLAINS AND LOWER FOOTHILLS. PRECIPITABLE WATER VALUES ARE IN THE 0.85 TO 1.20 INCH RANGE MONDAY NIGHT. TUESDAY INTO WEDNESDAY NIGHT...VALUES ARE PROGGED IN THE 1.10 TO 1.60 INCH RANGE...WITH THE HIGHEST AMOUNTS OVER THE EASTERN PLAINS. BOTH MODELS HAVE A PRETTY DECENT THETA-E AXIS OVER THE EASTERN TWO-THIRDS OF THE FORECAST AREA THROUGH THE PERIODS. THERE IS PRETTY DECENT CAPE PROGGED OVER THE NORTHEASTERN QUARTER OF THE FORECAST AREA MONDAY EVENING...THEN AGAIN OVER ALL AREAS EAST OF THE DIVIDE FOR LATE DAY TUESDAY INTO WEDNESDAY EVENING. THE LAPSE RATE FIELDS CONTINUE TO SHOW WEAK MID LEVEL CAPPING THROUGH THE PERIODS. MODELS HAVE A TAD OF MEASURABLE RAINFALL MONDAY EVENING...MORE SO ON THE NAM. THERE IS A BIT MORE FOR LATE DAY TUESDAY...BUT NOT MUCH AS FAR AS COVERAGE GOES. THERE IS MORE MEASURABLE PRECIPITATION INDICATED FOR LATE DAY WEDNESDAY. SO FOR POPS...CLEARLY THE MOISTURE GETS BETTER...BUT NOT SURE ABOUT THE LACK OF COOLING ALOFT. THERE IS UPSLOPE PROGGED AS WELL. WILL GO WITH OR KEEP IN...MAINLY..."CHANCES" FOR BOTH LATE DAY TUESDAY AND LATE DAY WEDNESDAY. FOR TEMPERATURES...TUESDAY'S HIGHS ARE AROUND 10 C COLDER THAN MONDAY'S HIGHS ACCORDING TO THE NAM...WITH THE GFS HAVING ONLY A 2-4 C COOL DOWN. WEDNESDAY'S HIGHS WILL BE CLOSE TO TUESDAY'S. FOR THE LATER DAYS...THURSDAY THROUGH SUNDAY ...THE MODELS HAVE THE UPPER RIDGE CENTERED AROUND ARKANSAS ON THURSDAY...WITH A WEAK UPPER TROUGH TO MOVE ACROSS THE FORECAST AREA ON FRIDAY. A SLIGHTLY WEAKER UPPER RIDGE MOVES BACK INTO THE STATE FOR SATURDAY AND SUNDAY. MOISTURE STILL SEEMS OK...SO WILL KEEP SOME MINOR POPS MENTIONED FOR THE "LATE IN THE DAY" PERIODS. TEMPERATURES STILL LOOK TO BE AROUND NORMALS. && .AVIATION...ISOLATED STORMS ARE EXPECTED TO MOVE FROM THE FOOTHILLS TO THE URBAN CORRIDOR THIS AFTERNOON. THESE STORMS ARE EXPECTED TO PRODUCE LIGHTNING AND GUSTY OUTFLOW WINDS TO 35 KNOTS UNTIL EARLY EVENING...THEN MOVE EAST. && .BOU WATCHES/WARNINGS/ADVISORIES...NONE. RTG/RJK
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER CO 1036 AM MDT SUN JUL 18 2010 COZ030>051-191200- 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- 1036 AM MDT SUN JUL 18 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS WILL AGAIN DEVELOP THIS AFTERNOON ACROSS THE FORECAST AREA. THESE STORMS WILL PRODUCE WIND GUSTS TO 45 MPH...SPORADIC LIGHTNING...AND BRIEF PERIODS OF RAIN. BETTER LOW LEVEL MOISTURE IN EXTREME NORTHEAST COLORADO WILL ALLOW FOR A FEW SEVERE STORMS WITH LARGE HAIL AND DAMAGING WINDS TO DEVELOP LATE THIS AFTERNOON AND EVENING. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THERE WILL BE A SLIGHT CHANCE OF LATE DAY SHOWERS AND THUNDERSTORMS FOR ALL THE FORECAST AREA MONDAY...FRIDAY AND SATURDAY. THERE WILL BE A CHANCE OF LATE DAY SHOWERS AND THUNDERSTORMS TUESDAY THROUGH THURSDAY. TEMPERATURES LOOK TO BE ABOVE SEASONAL NORMALS AGAIN ON MONDAY...THEN COOL TO NEAR NORMALS FROM TUESDAY INTO NEXT WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. RTG/RJK
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 354 PM MDT SUN JUL 18 2010 COZ048-182245- LOGAN COUNTY CO- 354 PM MDT SUN JUL 18 2010 THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN LOGAN COUNTY AT 354 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND WIND GUSTS TO AROUND 55 MPH. THIS STORM WAS LOCATED 10 MILES NORTH OF WESTPLAINS...OR 32 MILES NORTHWEST OF STERLING...MOVING EAST AT 10 MPH. LOCATIONS IN THE ADVISORY INCLUDE BUT ARE NOT LIMITED TO WESTPLAINS. PRECAUTIONARY/PREPAREDNESS ACTIONS... GUSTY WINDS FROM THE STORM MAY PRODUCE AREAS OF REDUCED VISIBILITIES IN BLOWING DUST. FURTHERMORE...THE WINDS MAY BE STRONG ENOUGH TO BLOW AROUND LOOSE OBJECTS SUCH AS OUTDOOR PATIO FURNITURE AND TRASH CANS. && LAT...LON 4100 10326 4082 10333 4083 10356 4100 10357 TIME...MOT...LOC 2154Z 262DEG 9KT 4101 10353
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 410 PM MDT SUN JUL 18 2010 COZ047-182245- SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN COUNTY CO- 410 PM MDT SUN JUL 18 2010 THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN LINCOLN COUNTY AT 409 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM CAPABLE OF PRODUCING WIND GUSTS TO AROUND 55 MPH. THIS STORM WAS LOCATED OVER EXTREME SOUTHWESTERN LINCOLN COUNTY...OR 42 MILES SOUTHWEST OF LIMON...MOVING SOUTHEAST AT 15 MPH. THE THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF THE ADVISORY COUNTY. PRECAUTIONARY/PREPAREDNESS ACTIONS... GUSTY WINDS FROM THE STORM MAY PRODUCE AREAS OF REDUCED VISIBILITIES IN BLOWING DUST. FURTHERMORE...THE WINDS MAY BE STRONG ENOUGH TO BLOW AROUND LOOSE OBJECTS SUCH AS OUTDOOR PATIO FURNITURE AND TRASH CANS. && LAT...LON 3886 10381 3853 10383 3853 10405 3887 10405 TIME...MOT...LOC 2209Z 262DEG 9KT 3872 10403
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 428 PM MDT SUN JUL 18 2010 COZ042-048-182315- LOGAN COUNTY CO-NORTHEAST WELD COUNTY CO- 428 PM MDT SUN JUL 18 2010 THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SIGNIFICANT WEATHER ADVISORY FOR WESTERN LOGAN COUNTY NORTHEASTERN WELD COUNTY AT 427 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF THUNDERSTORMS CAPABLE OF PRODUCING PENNY SIZE HAIL...AND WIND GUSTS TO AROUND 55 MPH. THIS STORMS WERE LOCATED FROM NEAR PAWNEE BUTTES TO WESTPLAINS...MOVING SOUTHEAST AT 15 MPH. LOCATIONS IN THE ADVISORY INCLUDE BUT ARE NOT LIMITED TO WILLARD... WESTPLAINS...STONEHAM...PEETZ...PAWNEE PASS...PADRONI...NORTH STERLING RESERVOIR...NEW RAYMER...LOGAN CORNERS...ATWOOD AND STERLING. PRECAUTIONARY/PREPAREDNESS ACTIONS... THESE STORMS 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. GUSTY WINDS FROM THE STORM MAY PRODUCE AREAS OF REDUCED VISIBILITIES IN BLOWING DUST. FURTHERMORE...THE WINDS MAY BE STRONG ENOUGH TO BLOW AROUND LOOSE OBJECTS SUCH AS OUTDOOR PATIO FURNITURE AND TRASH CANS. && LAT...LON 4099 10310 4054 10312 4053 10395 4099 10385 TIME...MOT...LOC 2227Z 288DEG 14KT 4083 10367
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE DENVER CO 450 PM MDT SUN JUL 18 2010 COZ040-041-045-182330- CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES CO- NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/EAST BROOMFIELD COUNTY CO- ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET CO- 450 PM MDT SUN JUL 18 2010 THE NATIONAL WEATHER SERVICE IN DENVER HAS ISSUED A SIGNIFICANT WEATHER ADVISORY FOR CENTRAL ARAPAHOE COUNTY SOUTH CENTRAL ADAMS COUNTY AT 450 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND WIND GUSTS TO AROUND 50 MPH. THIS STORM WAS LOCATED 4 MILES SOUTHWEST OF STRASBURG...OR 32 MILES EAST OF DENVER...MOVING EAST AT 10 MPH. LOCATIONS IN THE ADVISORY INCLUDE BUT ARE NOT LIMITED TO STRASBURG... BYERS AND BENNETT. PRECAUTIONARY/PREPAREDNESS ACTIONS... GUSTY WINDS FROM THE STORM MAY PRODUCE AREAS OF REDUCED VISIBILITIES IN BLOWING DUST. FURTHERMORE...THE WINDS MAY BE STRONG ENOUGH TO BLOW AROUND LOOSE OBJECTS SUCH AS OUTDOOR PATIO FURNITURE AND TRASH CANS. && LAT...LON 3984 10405 3958 10407 3958 10455 3985 10446 TIME...MOT...LOC 2250Z 277DEG 18KT 3969 10430
The Cheyenne radar (KCYS), 152 km away, was scanning. The volume nearest the first event began at 23:38 UTC.
3 thunderstorm wind, 1 tornado. Local standard time, as filed.
Intense thunderstorm winds blow a few 50 lb. hay bales 80 to 100 feet.
A tornado touched down in an open field briefly but did no damage.
Damaging thunderstorm winds snapped tree branches, 6 inches in diameter and larger. In addition, a roof to a structure under construction was damaged in Iliff and the material tossed.
Intense thunderstorm winds knocked a row of power lines down. In addition, an estimated 500 lb deck was lifted approximately 15 to 20 ft. off its platform.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2010Every state in 2010This day in weather historyThe tornado archive for Colorado, 2010Warnings in Colorado, July 2010
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: 251443, 251441, 251440, 251445.