A slow moving storm system produced flooding and flash flooding across the urban corridor and northeast plains, with heavy snowfall in the higher mountains of the Front Range.  Storm total rainfall during the 3-day event ranged from 4 to 7 inches across the urban corridor and Palmer Divide, with 2 to 5 inches across the plains.  Additionally, from 1 to 2 feet of heavy wet snow occurred above 10 thousand feet.  The heaviest rainfall occurred over Arapahoe, Denver, Douglas, Elbert and southern Jefferson counties.  Consequently, swollen creeks and streams produced flooding and flash flooding.  Numerous roadways were damaged or completely washed out including access roads to Cherry Creek State Park and National Wildlife Refuge at the Rocky Mountain Arsenal.  Numerous hiking trails in Castlewood Canyon State Park were closed as they were underwater and impassable. Dozens of roads in Adams and Weld counties were hit by flooding and were closed due to damage.  In Denver, a 24-hr daily record of 2.92 inches occurred on the 11th, with a 3-day total of 4.40 inches from the 10th-12th.  Three men in the foothills of Douglas County had to be rescued when their vehicle got stuck in snow along Rampart Range Road in Pike National Forest.  The heavy snow toppled trees which blocked the road.  Rescuers had to use chainsaws to cut through the downed trees to reach the stranded men; the rescue took nearly 21 hours to complete.

Winter Weather in JEFFERSON & W DOUGLAS COUNTIES ABOVE 6000 FEET / GILPIN / CLEAR CREEK / NE PARK COUNTIES BELOW 9000 FEET, COLORADO
From 11-MAY-23 11:00:00 to 12-MAY-23 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Three men in the foothills of Douglas County had to be rescued when their vehicle got stuck in snow along Rampart Range Road in Pike National Forest.  The heavy snow toppled trees which blocked the road.  Rescuers had to use chainsaws to cut through the downed trees to reach the stranded men; the rescue took nearly 21 hours to complete.

Flood in ARAPAHOE, COLORADO
From 12-MAY-23 05:00:00 to 13-MAY-23 05:00:00 (MST-7)
Location: PARKER
Flood cause: Heavy Rain
Property damage: 50.00K
Crop damage: 10.00K
Reported by: Broadcast Media

The heavy rainfall has caused road damage in Cherry Creek State Park, along East Lake View Road.  This resulted in the closure of the east and west boat ramps at Cherry Creek Reservoir.

Flood in DOUGLAS, COLORADO
From 12-MAY-23 05:00:00 to 13-MAY-23 05:00:00 (MST-7)
Location: CASTLEWOOD CANYON STATE PARK
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 10.00K
Reported by: State Official

Several trails in Castlewood Canyon State Park were closed as they were underwater and impassable.

Flood in ADAMS, COLORADO
From 11-MAY-23 14:00:00 to 12-MAY-23 08:00:00 (MST-7)
Location: NORTHGLENN
Flood cause: Heavy Rain
Property damage: 1.00M
Crop damage: 250.00K
Reported by: Emergency Manager

Dozens of roads in Adams County were hit by flooding and were closed due to damage. Authorities believe the damage and impact to the county was severe.  The following streets were closed due to flooding:  26th Ave. between Yulle Road and Wolf Creek Road, 64th Ave. between Piggott Road and Wolf Creek Road, Piggott Road from 80th Ave. to 88th Ave., Old Victory Road from US 36 to SH 79, 72nd Ave. from Bradbury-Krebs Road to Xmore Road, Road 15 from Bradbury-Krebs Road to Xmore Road, 26th Ave. from Strasburg Road to Comanche Drive, 26th Ave. from Piggott Road to Yulle Road, 48th Ave. from Strasburg Road to Piggott Road, 112th Ave. from Headlight Road to Nordbye Road, 112th Ave. from Behrens Road to Horrogate Road, 72nd Ave. from Converse Road to SH 79, 80th Ave. from Schumaker Road to SH 79, Cameron Drive from Guy Court to O���Brien, Converse Road from 128th Ave. to 144th Ave., Converse Road, from 88th Ave. to 112th Ave., East 112th Ave. from SH 79 to Converse Road, 104th Ave. at Manilla Road and at Tumbleweed Court, 64th Ave. from Converse Road to Schumaker Road, Converse Road from 88th Ave. to 64th Ave., 72nd Ave. at Converse Road and SH 79, 80th Ave. from SH 79 to Schumaker Road, 112th Ave. from Himalaya Road to Picadilly.  All Adams County trails were also closed, which included the South Platte River Trail.
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Flood in WELD, COLORADO
From 11-MAY-23 05:00:00 to 12-MAY-23 05:00:00 (MST-7)
Location: DACONO
Flood cause: Heavy Rain
Property damage: 1.00M
Crop damage: 250.00K
Reported by: Emergency Manager

Weld County closed 23 sections of county roads due to flooding.  Roads that were closed or damaged included:  Weld County Road 4 from County Roads 15-17, Weld County Road 6 from County Road 23-U.S. 85, Weld County Road 8 from County Road 23-U.S. 85, Weld County Road 10 from CO 79 - County Road 71, Weld County Road 10, from County Road 81-83, Weld County Road 14 from County Road 85-87, Weld County Road 15, from County Road 2-4, Weld County Road 16 from County Road 71-73, Weld County Road 16 from County Road 73-77, Weld County Road 17 from County Road 34-38, Weld County Road 42 from County Road 45-47, Weld County Road 48 from County Road 43-45, Weld County Road 50 from County Road 59-61, Weld County Road 57  from County Road 76-78, Weld County Road 61, from U.S. 34-County Road 50, Weld County Road 63 from U.S. 34-County Road 52, Weld County Road 72 from County Road  33-35, and Weld County Road 74 from CO 392-County Road 79.

Winter Storm in S & SE GRAND / W CENTRAL & SW BOULDER / GILPIN / CLEAR CREEK / SUMMIT / N & W PARK COUNTIES ABOVE 9000 FEET, COLORADO
From 10-MAY-23 19:35:00 to 12-MAY-23 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Storm totals included 27 inches at Berthoud Pass, 21 inches near Winter Park, 18 inches near Echo Lake, 17 inches near Loveland Pass, 14 inches, 8 miles south-southwest of Copper Mountain; 11 inches near Guanella Pass, with 10 inches near Green Mountain Reservoir.

Winter Weather in C & SE PARK COUNTY, COLORADO
From 10-MAY-23 11:00:00 to 12-MAY-23 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Storm totals included 10 inches, 7 miles east of Blue River and 9 inches, 5 miles north of Alma.

Winter Weather in WEST JACKSON & WEST GRAND COUNTIES ABOVE 9000 FEET, COLORADO
From 11-MAY-23 11:00:00 to 12-MAY-23 05:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Storm totals included 9 inches, 9 miles south-southeast of Gould.

Winter Weather in S & E JACKSON / LARIMER / N & NE GRAND / NW BOULDER COUNTIES ABOVE 9000 FEET, COLORADO
From 10-MAY-23 21:00:00 to 12-MAY-23 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SNOTEL

Storm totals included:  16 inches near Trail Ridge, 10 inches near Brainard Lake, with 8 inches near Eldora and Ward.