Flash Flood Prediction Program - 2013 Summary

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2015 Season Summary

Meteorological support services for 2015 are provided by Genesis Weather Solutions and Skyview Weather.

Click on the date hyperlink to see gauge and radar derived precipitation estimates for each event.

 

 

 

 

 

 

 

 

> 0.6" RADAR ESTIMATE OR 0.5" GAUGED IN FORECAST AREA

Event

Date

Max ALERT

Max CoCoRaHS

QPE STP

ALERT

Alarms

ALERT

Rain

Alarms

Note

ADAM

ARAP

AURA

BLDR

BROM

DENV

DOUG

JEFF

1
1.81"
1.27"
>3.50"

Message 1 issued at 1253 for the entire District.

An upper level low storm moving from SW Arizona to NE Colorado produced showers and thunderstorms. All District counties received moderate to heavy rainfall. The heaviest rainfall occured across Adams, Denver, Jefferson and Boulder Counties. One rainfall alarm was reported for Plains and two were recorded for Boulder County.

X
X
X
X
X
X
X
X
2
1.18"
1.16"
>1.00"

Message 1 Update issued at 0857 for the entire District. The system from SW Arizona was tracked across NE Colorado. Large cells without lightning moved from SE to the NW across the District. Denver County, NW Adams County and northern Jefferson County received the highest amounts of rainfall. No rainfall alarms were recorded on this day.

X
X
   
X
X
X
X
3
0.59"
0.77"
>1.00"

Message 1 issued for all Counties at 1309. Thunderstorms developing over Jefferson County moved towards Adams County creating periods of heavy rain. A gauge recorded 1.40" in the Thornton area. No rain alarms were recorded on this day.

X
             
4
1.18"
1.12"
>0.70"

Message 1 issued for all Counties at 1033. Heavy rainfall began which continued over the next two days. Boulder and Jefferson Counties received flooding due to ground saturation from earlier storms. Rainfall ranged from 0.10"-1.10"+. No rainfall alarms reported on this day.

X
   
X
X
X
X
X
5
2.13"
2.18"
>2.00"

Message 1 continued from the previous day. Heavier rainfall and snow were reported this day. Four rainfall alarms were triggered — one for Rampart Range Road and the other three for Jefferson County. Rainfall in the District ranged from 0.50"-2.00"+.

X
X
X
X
X
X
X
X
6
1.02"
3.00"
>2.50"

Message 1 continued for the third day. A large percentage of moisture resulted from snowfall. There was one rainfall alarm reported for Boulder County. Rainfall in the District ranged from 0.75"-2.75"+.

X
X
X
X
X
X
X
X
7
0.43"
0.33"
>1.00"

Message 1 issued for the entire District at 1237. In the early afternoon thunderstorms developed in parts of the District. The developed storm moved southwest to northeast and intensified as it reached Aurora. Hail up to 1.5" was reported in eastern Aurora as well as heavy rainfall with hail across Arapahoe and Adams Counties. Areas east of E-470 received the higher rainfall. A large cell also crossed over Boulder County. No rain alarms were recorded on this day.

X
X
X
X
   
X
X
8
1.06"
1.19"
>1.00"

Message 1 issued for the entire District at 1722 and continued until 5/19. An upper level low moved from SW Arizona to NW Colorado. Many rain showers and weak thunderstorms produced moderate to heavy rainfall across all District counties. Boulder and Jefferson Counties experienced more intense storms. No rain alarms were recorded on this day.

X
X
X
X
X
X
X
X
9
1.06"
0.99"
>0.70"

Message 1 Update issued at 0853. Message 2 issued for Boulder County, Jefferson County and Douglas County at 0904. Thunderstorms from the previous day continued throughout 5/19 in the given counties. No rain alarms were recorded on this day.

X
   
X
     
X
10
0.67"
0.82"
>1.00"

Message 1 issued for all Counties at 1619. Not much activity occured until mid-afternoon when thunderstorms developed to the West and South of the District. Strong systems remained mostly outside of the District. Douglas county experienced hail but not much rain. Mostly moderate rain with intermittent heavy rainfall. Lighter rain continued into the night. No rain alarms were recorded on this day.

X
       
X
X
X
11
0.75"
0.97"
>1.43"

Message 1 issued for all Counties at 1048. In the afternoon storms filled the plains, generally moving from south to north. Thunderstorms continued in the afternoon and early evening with initial bands between 1230 and 1430. NWS Aerial Flood Advisory issued for Jefferson, Denver, Adams, and Broomfield County from 1338 to 1545. No rain alarms were recorded on this day.

X
X
X
X
X
X
X
X
12
0.31"
0.47"
>0.65"

Message 1 issued for all Counties at 1109. Strong thunderstorms produced a flash flood warning for Elbert and Arapahoe Counties. Weaker storms moved over western parts of the District in the afternoon. No rain alarms were recorded on this day.

             
X
13
0.87"
1.31"
>1.21"

Message 1 issued for all Counties at 1726. A late afternoon thunderstorm over Boulder County and west of I-25 produced heavy rainfall (>1") and accumulating hail. No rain alarms were recorded on this day.

 
X
 
X
 
X
X
X
14
0.47"
0.67"
>0.81"

Message 1 issued for DIA as well as Adams, Jefferson, Arapahoe, and Aurora Counties at 1822. Rainfall between 0.30" and 0.80" in 10-30 minutes was recorded. Moderate rainfall reported for all given counties. No rain alarms were recorded on this day.

X
X
     
X
 
X
15
0.67"
0.86"
>1.33"

Message 1 issued for Boulder, Jefferson and Douglas Counties at 1304. Rainfall measured from 0.40"-1.10" in 10-30 minutes and large hail in certain areas.. Message 1 was also issued for DIA as well as Arapahoe, Aurora, Denver and Broomfield Counties.No rain alarms were recorded on this day.

X
X
X
X
X
X
X
X
16
0.47"
0.48"
>0.60"

Message 1 issued for Boulder County, Jefferson County, and Douglas County at 1451. No rainfall over 0.50" was reported. No rain alarms were recorded for this day.

           
X
 
17
0.55"
0.23"
>2.47"

Message 1 issued for Jefferson, Douglas, Arapahoe and Aurora Counties at 1301. Rainfall accmulation fell between 0.40" and 1.10" in 10-30 minutes.

X
         
X
X
18
1.50"
1.25"
>1.63"

Message 1 issued for all Counties at 1048. Heavy rainfall and strong thunderstorms accumulated in the afternoon producing hail. Southern Arapahoe, Jefferson and Douglas counties received the heaviest rains. The District received 9 seperate severe thunderstorm warnings as well as multiple rainfall alarms. Only Douglas and Arapahoe counties reported rainfall greater than 1.00".

X
X
X
   
X
X
X
19
1.97"
1.56"
>3.68"

Message 1 issued for the entire District at 1400. Rainfall was recorded between 0.50" and 1.30" in 10-30 minutes.A storm tracked from southern California produced hail up to 1.75" in diameter in the Denver Metro area. Many ALERT rainfall alarms were active in the 36-hour period.

X
X
X
X
X
X
X
X
20
1.69"
2.02"
>2.65"

Message 1 continued from the previous day. All counties observed heavy rainfall and a few received hail. Rainfall from 0.45"-3.00" was reported over the 36-hour period. Many ALERT rainfall rate alarms were active.

X
X
X
X
X
X
X
X
21
0.67"
0.64"
>1.18"

Message 1 issued for all Counties at 1158. Heavier rainfall was concentrated over Denver, Adams and Douglas Counties. No rainfall measurments exceeded 1.00". Rainfall alarms were triggered in Denver County.

 
X
 
X
 
X
X
X
22
1.54"
1.82"
>2.06"

Message 1 issued for all Counties at 1639. A large thunderstorm developed quickly over the Denver Metro area. The slow-moving storm headed into Adams County and triggered an urban/small stream flood advisory for Adams and Denver Counties. Some areas received 0.50"-1.00" of rain and isolated areas received over 1.50" of rain on this day.

X
X
X
X
X
X
X
X
23
0.83"
1.01"
>1.61"

Message 1 issued for Jefferson County, Adams County and Broomfield County at 1744. Message 1 issued for Boulder County, Denver County, Arapahoe County, Aurora and DIA at 1816. Moderate to heavy rainfall observed in the central and eastern portions of the District.

X
X
X
       
X
24
0.94"
1.41"
>1.12"
Message 1 issued for the entire District at 1406. Strong thunderstorms developed in the southern portions of the District specifically in Douglas County. Rainfall alarms were triggered in Douglas County.            
X
X
25
3.62"
3.84"
>3.83"
Message 2 issued for the entire District at 0835. Message 3 issued for Arapahoe County, Douglas County and Aurora at 1719. Strong thunderstorms developed throughout the District beginning at about 3pm and into the evening. Numerous rainfall alarms were triggered with rates exceeding 1"/hour in Boulder County, on the Plains and in Douglas County.
X
X
X
X
X
X
X
X
26
0.91"
1.02"
>0.96"
Message 3 issued for Douglas County at 0714. Message 1 issued for remainder of the District at 0721. Early morning showers with moderate to heavy rainfall were observed in Douglas County, Denver, Jefferson County and Boulder County. Concern for flash flooding was present as the previous day dropped heavy rain which saturated the ground. Rain stopped around noon with no further activity for the remainder of the day.
X
X
 
X
 
X
X
X
27
0.79"
0.87"
1.99"
Message 1 issued for Adams County, Denver County, Arapahoe County including DIA at 1809. Message 1 issued for the remainder of the District at 1843. Message 3 issued for Adams County and DIA at 1908. Large thunderstorm observed in Adams County and DIA which produced large hail and heavy rain. Moderate rainfall observed in several portions of the District.
X
X
X
X
X
X
X
X
28
0.35"
0.50"
>1.03"
Message 1 issued for Boulder County, Jefferson County and Douglas County at 1311. Message 1 issued for Adams County at 1959. Several small thunderstorms and showers developed in the western portions of the District. One large thunderstorm moved through Adams County. Heavier rainfall also observed in Douglas County.
X
         
X
 
29
0.28"
0.29"
>1.00"
Message 1 issued for entire District at 1541. Several small thunderstorms moved through the District. Heavier rainfall observed in Boulder County and Douglas County.            
X
 
30
0.35"
0.20"

>1.72"

    Message 1 issued for Douglas County at 1701. Message 1 issued for Arapahoe County and Aurora at 1716. Moderate rainfall observed with some hail.  
X
       
X
X
31
0.24"
0.27"
>0.69"
Message 1 issued for the entire District at 2053. Light to moderate rainfall observed in Jefferson County.              
X
32
0.39"
0.29"
>0.67"
Message 1 issued for Denver County, Jefferson County, Arapahoe County, DIA, Douglas County and Adams County at 1923. Light to moderate rainfall observed in portions of Denver County, Arapahoe County, Aurora and Douglas County.            
X
 
33
2.24"
3.31"
1.85"
Message 1 issued for all areas at 1603. Message 3 issued for Arapahoe/Aurora, Adams, and Denver county at 1726. Message 3 update for Arapahoe/Aurora, Adams, and Denver county at 1923. Message 1 update for all areas not under M3 at 1944. Severe thunderstorms developed over Denver and produced heavy rain and large hail from 430 pm to 630 pm. Light showers persisted in the Denver and Boulder area into the evening. The South Platte River at 19th Street hit the 4th highest peak on record during this storm. The period of record for this site is more than 100 years.
X
X
X
X
 
X
X
X
34
1.57"
1.52"
2.19"
Message 1 issued for the entire District at 1552. Moderate thunderstorms developed within the District between 4 pm and 8 pm. Heavy thunderstorm developed in Douglas County triggering alarm amounts of 0.5" in 10 minutes and 1.0" in 1 hour at Russellville Gulch and East Cherry Creek.
X
X
 
X
 
X
X
X
35
1.22"
1.08"
1.09"
Message 1's issued for Boco, Jeffco, and Dougco at 1446 valid until 2100. 0.40-0.90" rainfall in 10-30 min. Moderate to strong thunderstorms moved through the western part of the District. Storms weakened as they moved over the lower elevations of the District due to a stable air mass that was in place. Boulder, werstern Jefferson and central Douglas county experieced moderate to heavy rainfall.
X
X
 
X
 
X
X
X
36
0.79"
0.60"
0.98"
Message 1's issued for all areas except Broomfield at 1826 effective 1845. Message 1 issued for Broomfield at 1856. Around 700 pm thunderstorms moved into the northern parts of the District which produced moderate rain with a few areas experiencing heavy rain, mainly over Boulder County foothills. The line of storms moved south and intensified producing additional pockets of heavy rainfall over Douglas County. Storms exited District around 930 pm. Rainfall totals remained under 1".
X
       
X
X
 
37
0.59"
0.60"
0.72"
Message 1's issued for all areas at 1541. Thunderstorms developed over the foothills around 3 pm. Fast storm motion kept rain totals under 0.50". The heaviest rains were over Boulder and Douglas County with a few isolated areas in Denver County
X
   
X
 
X
X
X
38
1.22"
1.14"
1.29"
Message 1's issued for Boco, Jeffco and Dougco at 1313 valid until 2100. 0.40-0.90" rainfall in 10-30 min. Message 1's issued for Arapco and Aurora at 1716 valid until 2100. 0.40-0.90" rainfall in 10-30 min. Multiple waves of rain showers and thunderstorms moved over the westen portions of the District. Moderate to heavy rainfall was observed in western Jefferson County, northern Douglas County and western Boulder County.      
X
   
X
X
39
1.02"
1.12"
1.42"
Message 1's issued for Boulder, Jefferson and Douglas at 1250. Message 1's issued for Arvada, Wheat Ridge and Lakewood at 1251. Message 1's issued for all other areas at 1346. Rain and isolated thunderstorms developed over the higher terrain by around noon. Around 2 pm storms began to survive over the lower elevations. Rain showers and isolated thunderstorms would continue into the late afternoon with some breaks in the evening. Light rainfall would continue into the night.
X
   
X
X
X
X
X
40
2.91"
2.72"
2.75"
Message 1's issued for the entire District at 1333. A few strong storms initially developed over the southern foothills by early afternoon. The cap finally broke over the northern portions of the District after 5 pm allowing thunderstorms to develop across northern Jefferson, northern Denver and Adams counties as well as the Boulder foothills. Heavy storms produced large rain totals from Arvada to Commerce City to Henderson. 2.91" fell at the Little Dry at 64th gauge. Thunderstorms decreased after 8 pm although light rain showers continued well into the evening. The heaviest totals occurred over Adams, northern Jefferson, extreme north Denver county and the Boulder foothills.
X
X
 
X
X
X
X
X
41
0.83"
0.69"
1.45"
Message 1's issued for the entire District at 2118. A late day upper disturbance triggered a strong thunderstorm cluster over the southern foothills during the evening. The cluster held together and moved across the District from southwest to northeast from southern Jefferson County to Denver to Adams/DIA from about 9 pm to 11:30 pm. Lightning was more of a threat than heavy rainfall but due to slow storm motion and some strengthening over the northeast portions of the District, pockets of moderate to heavy rainfall occured, with 0.83" at Henderson and 0.55" at DIA. The highest rainfall totals occured over Broomfield and Adams county.
X
X
     
X
X
X
42
1.06"
0.48"
2.37"
Message 1's issued for Boulder, Jefferson, and Douglas counties at 1313 valid until 2100. 0.40-0.90" rainfall in 10-30 min. Up to 1.35" in 15-45 min. A line of moderate to strong thunderstorms moved through the western portion of the District. Line weakened as it moved over the lower elevations of the District. Moderate to heavy rainfall was observed in southwest Boulder County and western Jefferson County.
X
   
X
     
X
43
0.79"
0.50"
1.67"
Message 1’s issued for the entire District at 1418.  With rainfall 0.40-1.20” in 10-30 min forecast. Thunderstorms developed over the eastern portion of the District. Moderate to heavy rainfall was experienced across Adams County, northwest Aurora, Arapahoe County, northeast Denver County, DIA, and Broomfield County.
X
X
 
X
 
X
   
44
0.79"
0.67"
0.96"
Message 1's issued for the entire District at 1544. The back edge of a monsoon moisture plume moved overhead in the late mid afternoon, producing a round of moderate to strong thunderstorms which traversed the District from WNW to ESE from 4 pm to 6 pm. Aerial flood advisory issued by the NWS for Adams and Broomfield Counties from 4:47 pm to 6:15 pm. Multiple areas with 0.4-0.5" per 10 min.
X
X
X
X
X
 
X
X
45
1.26"
0.58"
1.12"
Message 1's issued for the entire District at 1519. As light storms moved into the eastern areas of the District, moisture levels increased and storms strengthened. This produced brief heavy rain over Adams and Arapahoe counties after 3 pm. A couple rounds of storms were experienced through 7 pm but no significant storms after 7 pm. A couple UDFCD rainfall rate alarms were triggered with totals generally under 1" with the execption of "Pump Station #3" which reported a daily total of 1.26".
X
X
X
   
X
   
46
1.04"
0.43"
0.32"
Message 1’s issued for the entire District at 1307. 0.40-1.20” of rainfall in 10-30 min forecast. Mountain thunderstorms moved into the District but weakened. Moderate to heavy rainfall was observed over southwest Douglas County and southern and central Jefferson County.            
X
 
47
2.13"
1.64"
1.17"
Message 1's issued for the entire District at 1129. Thunderstorms began to develop over the higher terrain before noon. A line of thunderstorms moved through the District
early/mid afternoon with the line moving from NW to SE, with the most intense storms in S and SE portions of the District producing heavy rainfall and some hail. NWS Aerial flood advisory issued for NW Douglas, W Arapahoe and Aurora from 145pm to 415pm.
X
X
X
X
 
X
X
X
48
1.10"
0.71"
2.53"
Message 1's issued for the entire District at 1322. Mountain thunderstorms weakened as the entered the District. No heavy rainfall was observed over the District.            
X
 
49
1.10"
1.48"
2.16"
Message 1's issued for Arapahoe, Aurora and Douglas at 1452. Slow moving thunderstorms developed over Arapahoe and Douglas counties. Moderate rainfall was observed.
X
X
X
   
X
X
X
50
0.35"
0.27"
0.60"
Message 1's issued for the entire District at 1602. Mountain thunderstorms weakened as the entered the District. No heavy rainfall was observed over the District.              
X
51
1.02"
1.05"
1.37"
Message 1's issued for Adams, Arapahoe/Aurora and Denver/DIA at 2345. Thunderstorms began to develop after 10PM with additional storms developing and re-developing.
X
X
X
   
X
   
52
1.30"
0.55"
1.19"
Message 1's issued for Adams, Arapahoe/Aurora and Denver/DIA at 2345 the previous day. Storm activity began to diminish by 2AM but continues until 4AM.
X
X
X
   
X
X
X
53
1.50"
1.84"
2.21"
Message 1's issued for the entire District at 1211. Message 3's issued for North Douglas, Arapahoe and Aurora at 1442. Mountain thunderstorms moved into lower elevations and generally weakened. A thunderstorm cell developed and produced heavy rain with 1.5" - 1.85" in 45-60 minutes.  
X
X
   
X
X
X
54
1.54"
1.66"
1.94"
Message 1's issued for the entire District at 1532. Abundant moisture in the area allowed thunderstorms to rapidly develop and remained stationary. Storms diminished by 1730.
X
X
X
   
X
X
 
55
0.24"
0.39"
0.84"
Message 1's issued for the entire District at 1910. A cluster of weak thunderstorms moved into the District but weakened. No heavy rainfall was observed.              
X
56
1.18"
1.05"
1.38"
Message 1's issued for Arapahoe/Aurora, Jefferson, Douglas and Denver/DIA at 1706. Moderate to heavy rain occured between 1730-1900. NWS Aerial Flood advisory was issued for central Jefferson County including a small portion of the District from 1725 - 1930. The heaviest rainfall fell over a small area of Jefferson, Arapahoe and Douglas counties. UDFCD gages did not capture the heaviest rainfall.  
X
       
X
X
57
0.24"
1.50"
2.12"
Message 1's issued for Arapahoe/Aurora, Jefferson, Douglas and Denver at 1611. Strong thunderstorms developed SW of the District in the afternoon. These slow moving storms produced heavy rainfall over the Hayman burn area and developed into small pulse storms producing mostly brief, moderate rainfall over the District. Heavy rainfall over the Hayman burn area resulted in 3 flash flood warnings.
X
         
X
X
58
1.97"
1.20"
1.52"
Message 1's issued for Arapahoe/Aurora, Douglas and Denver at 1900. Very warm daytime temperatures and favorable conditions produced thunderstorm activity over the District in the early evening. Widespread heavy rainfall did not occur over the District with these thunderstorms. Heaviest rainfall fell south of the District.  
X
     
X
X
X
59
0.79"
1.10"
1.09"
Message 1's issued for the entire District at 1518. An isolated strong/severe thunderstorm developed over NW Boulder County and tracked to the SSW across Boulder County, Four Mile Burn Area and NW Jefferson county. Moderate to heavy ranfall was measured over central Boulder County and NW Jefferson County.      
X
   
X
X
60
0.51"
0.57"
1.19"
Message 1's issued for the entire District at 1356. A line of fast moving thunderstorms moved across the District. Fast storm movement reduced point rainfall. Moderate to heavy rain was measured in Jefferson, Douglas, Arapahoe and Adams Counties.            
X
X
61
0.55"
0.60"
0.86"
Message 1's issued for the entire District at 1531. Fast moving thunderstorms moved across the District. Fast storm movement reduced point rainfall. Moderate to heavy rain was measured in northern Jefferson, Broomfield, SE Boulder and NW Counties.
X
X
       
X
X

 

 

Maximum 24-hour value

Maximum 24-hour value

Maximum

Radar

estimated

24-hour

precip

Alarm Log

Rainfall

Rate Alarm

 

ADAM

ARAP

AURA

BLDR

BROM

DENV

DOUG

JEFF