Issue Date: Thursday, August 18th, 2022
Issue Time: 9:45 MDT

Summary:

The Front Range and Urban Corridor finally got a break from the rain yesterday. Denver and Fort Collins saw a significant decrease in precipitation, with most observations reported as 0.05” or less. A few notable observations include 0.17” in Superior and 0.2” in Fort Lupton. Moving south, Colorado Springs and Pueblo saw the same trend, with reports of just 0-0.01″ observations as the majority for both cities. A severe thunderstorm warning was issued for southwest Lincoln County to the northwest of Pueblo, but the storm weakened and the warning ended shortly after it was issued.

Three flood advisories were issued yesterday, two west of Telluride and one southeast of Pagosa Springs bordering New Mexico. Within the flash flood warning boundary just west of Telluride, there was another debris flow over Highway 145, reported by CDOT at 3:44 PM. Placerville nearby received up to 0.8”, via CoCoRaHS, along with reports of moderate to heavy rain and thunder. 1.06” was also reported near Mancos, but that was the highest rainfall observed in the Southwest Slope region- most other observations were between 0” and 0.4”. In the San Luis Valley, up to 0.55” was reported, near Alamosa, while the Raton Ridge only saw up to 0.15”.

The Central Mountains saw up to 0.37” but similarly less than the last few days. The Grand Valley and Northwest Slope stayed dry, and the Eastern Plains followed suit with observations of only up to 0.02” via Mesowest gages.

The updated drought monitor was released today, shown below. Improvements include a decrease in the percentage of land in the Moderate and Severe Drought categories. However, percentages in the categories of None, Abnormally Dry, and Exceptional Drought stayed the same from last week.

If you observe flooding in your area, remember to use the “Report a Flood” page to make any flood reports when you can safely do so. For precipitation estimates in our area, check out the map below.

Click Here For Map Overview

Issue Date: Wednesday, August 17th, 2022
Issue Time: 10:25 MDT

Summary:

It was another active day for heavy rain across Colorado yesterday, and the Denver Metro Area/Urban Corridor saw an early start! By 9 AM, Broomfield had already received 3.5” of rainfall from a nearly stationary thunderstorm that lasted several hours.

In total, 3.70” was recorded in Broomfield in just 3 hours, which is 25% of the average annual rainfall! Throughout the afternoon, other areas of the city continued to see significant rainfall as well- up to 1.51” in Aurora. Two flood advisories were issued north of Denver, with many reports of streets, parks, and rivers with severe flooding specifically near Broomfield, Thornton, and Louisville. Some of the flooding events observed include:

• Rock Creek in Lafayette was completely submerged, with a report of at least 5 feet of water over the bike path
• 6” of water over Highway 287 in Broomfield
• Spader Way in Boulder was closed between 1st Ave. and DesCombes Drive due to flooding
• Continued flooding of Toll Gate Creek in Aurora
• Midway Park in Broomfield was severely flooded

Check out some of the flooding at a park in Broomfield, Colorado this morning.

The #Denver suburb received 3.70 inches of rain in just 3 hours today. For perspective, that’s 25% of their annual rainfall! #COwx pic.twitter.com/kFhE7u1ti9

— FOX Weather (@foxweather) August 16, 2022

Only one stream reached flood stage yesterday, this time at Sand Creek near Commerce City. View the hydrograph below to see the significant increase in discharge from rainfall Monday and Tuesday, which ultimately pushed the creek into minor flood stage yesterday morning.

The Southeast Plains and south-central part of the state also saw heavy rainfall and increased activity yesterday from afternoon and evening storms. In the Southeast Plains, highest totals include 2.58” via a trained spotter in Walsh and 2.28” near Las Animas via a Mesowest gage. Most other observations ranged from 0.1”-2”. Moving west, totals over the Raton Ridge to San Luis Valley were generally between 0.15”-1.5”, including up to 1.4” near Trinidad, 1.49” southwest of Pueblo, and 1.24” near Huerfano, via CoCoRaHS observations and Mesowest gages. The Southwest Slope was a bit drier yesterday however, with observations staying mostly under 0.5”.

In the Grand Valley, the Pine Gulch burn scar was issued a flash flood warning, but it was cancelled by 6 PM with no flooding reported. This area saw up to 0.86” according to a CoCoRaHS observer, although other observations generally stayed between 0”-0.64”. To the south, a debris flow consisting of minor mudslides over Highway 145 in Telluride was reported yesterday as well, but the highway was quickly cleared within a few hours. Rainfall near Telluride was 0.23” or less.

The Central Mountains also saw continued rainfall from the day before, with totals for the area reaching up to 1.16” in Silverthorne, but generally staying between 0”-1”.

The northern Front Range and Urban Corridor stayed relatively dry, with trace -0.05” observations. Thankfully, there was no flooding yesterday on the Cameron Peak burn scar, although the Poudre River was observed to be dark brown from mud and sediment runoff from the rain in the area on Monday.

If you observe flooding in your area, remember to use the “Report a Flood” page to make any flood reports when you can safely do so. For precipitation estimates in our area, check out the map below.

Click Here For Map Overview

Issue Date: Tuesday, August 16th, 2022
Issue Time: 10:45 MDT

Summary:

Yesterday saw early morning showers for the Southeast Plains, associated with a frontal boundary extending back into eastern Colorado from a low centered over Nebraska/South Dakota. These showers cleared out from west to east by mid-morning from daytime heating along with the northeastward progression of the associated low. The Eastern Plains received between 0-1.0” in most places with a few higher totals such as 1.57” in Vernon and 1.2” near Lincoln.

Further west, late morning daytime heating combined with above normal precipitable water from a plume of monsoonal moisture circling the high-pressure ridge to the southeast, which allowed for convection to develop across much of the high terrain in the western half of the state. Storms increased in coverage and intensity as the afternoon progressed, and slow steering flow expanded storms onto the Urban Corridor and Palmer Ridge as well. Slow storm motion combined with ample available moisture allowed for very heavy rainfall, especially under embedded convection.

By evening, there was widespread coverage of showers and thunderstorms across much of the state. Drying generally occurred from west to east, as the high-pressure ridge weakened and moved eastward. Still, showers and thunderstorms lasted well into the overnight hours and early morning for the Southeast Plains, Palmer and Raton Ridge.

The Urban Corridor received the bulk of the rainfall yesterday- Flood Advisories and Severe Thunderstorm warnings patchworked the area from north Aurora and southeast Denver all the way to west of Colorado Springs. From Castle Rock up to northwest Aurora received the heaviest precipitation from the storms, with most observations in and around the city between 1-2”, although southwest and northeast of the city received lower amounts generally under 1”. Some of the most significant precipitation totals are listed below:

• 2.91” in Louviers
• 2.91” in Aurora
• 2.83” west of Castle Rock
• 2.76” in Broomfield
• 2.60” near Cherry Creek State Park
• 2.48” southwest of Lone Tree

Flooding was significant due to the amount of rainfall that occurred. Below are reports of street flooding in Southeast Denver and nearby areas:

• South Chambers Road in Aurora was impassable due to flooding
• South Parker Road in Aurora was impassable
• 6 inches of water at Mansfield and E Loyola Drive in Foxfield
• 6-12 inches of water at East Bellevue Avenue and Syracuse in Greenwood Village
• Approximately 1 foot of water at the I-25 northbound on-ramp in Centennial- see below!
• Several feet of water flooding a basketball court in Lone Tree
• Several feet of water flooding a gas station lot in Aurora

This was flash flooding at I-25 and Arapahoe Rd (CO 88) around 3:30pm today. @NWSBoulder #cowx #flooding pic.twitter.com/d4Y64lIeqK

— Kyle Witter (@kyle_witter) August 16, 2022

Several stream gages in the eastern metro area of Denver saw significant increases in discharge, some even reaching minor flood stage during the peak of the storm. The hydrograph below is from a stream gage in southeast Aurora. You can observe the spike in streamflow, reaching minor flood stage (over 4 feet) for a brief period of time.

North of Colorado Springs, flooding was reported in Elbert County over CR 106, between CR 5 and 13. However, northwest of the city saw the most activity- overlapping flood advisories, a severe thunderstorm warning, and multiple reports of 1” hail. In that area, flash flooding was reported 3 miles west of Callaghan, with “1-2 inches falling in the past hour”. Flash flooding was also reported in Peyton, along with up to 1.7” of rainfall.

Found some hail north of Peyton. #cowx pic.twitter.com/M1eU1uL25p

— Matt Minnillo and Blue Thunder (@MattBlueThunder) August 15, 2022

Out in the Grand Valley, there were many Flood Advisories issued, including partial coverage of the Pine Gulch burn scar. However, this area saw relatively low totals compared to surrounding areas to the south and east; only up to 0.25” in Grand Junction. The Southwest Slope received higher amounts, including up to 0.89” in Montezuma (this CoCoRaHS observer stated “I’m not sure that I’ve ever had so much rain in my 16 or more years of measuring.”), 0.91” northeast of La Plata, while the Raton Ridge area saw up to 1.02” in Trinidad! Other observations in the southwest range from 0”-0.8”.

The Central Mountains and Front Range received up to 1.20” of rainfall, concentrated around the areas west of Colorado Springs and Denver. South of Glenwood Springs saw at least 0.82”, and I-70 was closed yesterday by 7:00 PM due to a Flash Flood Warning issued over the Grizzly Creek burn scar, but reopened a few hours later. No flooding or debris flows have been reported.

Higher totals of up to 1.6” were observed near Drake and Estes Park, near the southern edge of the Cameron Peak burn scar. Four flood advisories over the burn area between approximately 2:13 PM and 7:15 PM. At 2:30 PM, reports came in from Larimer County Office of Emergency Management of flooding on the burn scar, resulting in an extended closure of several roads in the Retreat neighborhood. By 2:39 PM, emergency management had closed the road due to rockslides about 2 miles east of Drake.

If you observe flooding in your area, remember to use the “Report a Flood” page to make any flood reports when you can safely do so. For precipitation estimates in our area, check out the map below.

Click Here For Map Overview

Issue Date: Monday, August 15th, 2022
Issue Time: 11:40 AM MDT

Summary:

The upper-level ridge to our southeast weakened some on Sunday, allowing increased monsoonal moisture across the state and wider coverage of precipitation. Storms developed over the mountains by mid-afternoon, with some cells able to track into the lower elevations of the Northeast Plains later in the day. Rain generally fell along and north of I-70; QPE data suggests the heaviest rain fell across Weld, Morgan, and Washington Counties, with localized amounts up to 3”.

West of Denver, two Flash Flood Warnings were issued along I-70, including one for the Grizzly Creek burn scar, although flooding on the scar itself could not be confirmed. The Colorado Department of Transportation temporarily closed portions of I-70 as a precaution, while flash flooding was observed in Glenwood Springs off of Transfer Trail Road, per video posted to Twitter:

Flash flooding captured in Glenwood Springs, CO off of Transfer Trail Rd after some big storms rolled in. Flash flooding warning still in effect for the Glenwood Canyon.@9NEWS @DenverChannel @WeatherBug @weatherchannel @wunderground @NWSGJT #cowx #Weather #glenwoodsprings pic.twitter.com/Xx95P4h19P

— Watts Brooks (@WattsBrooks1) August 15, 2022

Rainfall amounts of 2.04” and 1.04” were measured near Glenwood Springs. Additionally, a rockslide was reported along CO-131 at Old Bond Road, and a mudslide was reported along US-24 between Eagle River and FS Road 762. Several other flood reports were received by CDOT across the Central Mountains.

Further southwest across northwestern Ouray County, a Flood Advisory was issued, with members of the public reporting localized flooding near Montrose. 1.25” of rain in one hour was reported 6 miles southwest of Montrose, while a CoCoRaHS observer 12 miles southwest of Montrose measured a storm total of 0.95”; the 1.25”/hour report has an estimated ARI of 100 years!

Across the Northern Mountains and Front Range, heavy rainfall was also observed. Two Flood Advisories and one Flash Flood Warning were issued for portions of the Cameron Peak burn scar, but no flooding was reported. Notable rainfall totals across the Front Range include 1.53” north of Floyd Hill and 1.24” northeast of Estes Park.

Farther east across the Northeast Plains, storms prompted two Severe Thunderstorm Warnings and a Flood Advisory across northern Weld County. Notable rain gauge totals over the Plains include 1.06” near New Raymer, 1.02” near Briggsdale, and 1.00” near Woodrow. Check out this picture of flooding south of Grover:

Flooding over highway 390 south of Grover near the junction with 112. @NWSBoulder #cowx pic.twitter.com/SowuPux4lt

— Matt Ley (@Matt_wyo) August 15, 2022

If you observe flooding in your area, remember to use the “Report a Flood” page to make any flood reports when you can safely do so. For precipitation estimates in our area, check out the map below.

Click Here For Map Overview