Flash Flood, Merrimack
- When
- August 12, 1:30 AM EST to 3:00 AM EST
- Where
- Merrimack County, Contoocook
- Reported by
- EMERGENCY MANAGER
- Coordinates
- 43.298, -71.680 (the zone’s center; the record gives no point)
Flash Flood in New Hampshire, August 12, 2003
Thunderstorms produced 2 to 4 inches of rain in an hour and caused roads and streets to flood. Emergency Management Agency officials reported 3 ft of water over Route 4 in Chichester during the event.
Where it happened
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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.
What happened
The episode as NWS GYX wrote it up.
Thunderstorms produced 2 to 4 inches of rain in an hour and caused roads and streets to flood. Emergency Management Agency officials reported 3 ft of water over Route 4 in Chichester during the event.
What forecasters said that day
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 Gray, ME wrote its last area forecast discussion before the first event at Aug 11, 8:50 PM EST, 4 hours 40 minutes earlier.
Area forecast discussion, Aug 11, 8:50 PM EST, 4 hours 40 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 950 PM EDT MON AUG 11 2003 CONVECTIVE ACTIVITY DECREASING ACROSS FA. WILL GO WITH SCT SHRA REST OF THE NIGHT AS AIR BEHIND TSTMS MORE STABLE. UPDATED ZONES ALREADY SENT. NO OTHER MAJOR CHANGES NEEDED. .GYX...NIL SJB
Hazardous weather outlook, Aug 11, 3:13 AM EST, 22 hours 17 minutes before
MEZ007>009-012>014-018>028-NHZ001>010-013-014-111915- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAY ME 413 AM EDT MON AUG 11 2003 THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND SOUTHERN MAINE AND NORTHERN...CENTRAL AND SOUTHEAST NEW HAMPSHIRE. .DAY ONE...TODAY A FLOOD WATCH IS IN EFFECT FOR GRAFTON AND CARROLL COUNTIES IN NEW HAMPSHIRE THIS AFTERNOON AND TONIGHT. THESE COUNTIES HAVE RECEIVED VERY HEAVY RAINS OVER THE PAST FEW DAYS...AND SHOWERS AND THUNDERSTORMS THIS AFTERNOON MAY PRODUCE VERY HEAVY RAINS. THIS ADDTIONAL RAINS COULD RESULT IN FLOODING OF RIVERS AND STREAMS IN THE WATCH AREA. .DAYS TWO THROUGH SEVEN... NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE REQUIRED THIS AFTERNOON AND TONIGHT IN THE WATCH AREA. HAYES
In the hours before
Local storm report, Aug 11, 9:00 PM EST, 4 hours 30 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAY, ME
1000 PM EDT MON AUG 11 2003
TIME(EDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0839 PM POWNAL ME WIND DAMAGE
08/11/03 CUMBERLAND TREES AND POWER LINES DOWN.
4 REPORTS RCVD BETWEEN
839 PM TO 859 PMSpecial weather statement, Aug 12, 12:10 AM EST, 1 hour 20 minutes before
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
Special weather statement, Aug 12, 1:25 AM EST, 5 minutes before
NHZ008-120730- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GRAY ME 225 AM EDT TUE AUG 12 2003 ...A STRONG THUNDERSTORM WILL MOVE ACROSS CENTRAL MERRIMACK COUNTY THROUGH 325 AM... A STRONG THUNDERSTORM SOUTH OF BRADFORD AT 225 AM WILL MOVE NORTHEAST DURING THE NEXT HOUR. AS THE STORM PASSES BRADFORD... WARNER...WATERLOO AND WEBSTER...WIND GUSTS TO 35 MPH ARE POSSIBLE...AS WELL AS PEA SIZED HAIL. IN ADDITION...THIS STORM HAS THE POTENTIAL TO PRODUCE UP TO ONE AND ONE-QUARTER INCH OF RAIN IN LESS THAN 30 MINUTES. THIS WOULD RESULT IN STREET FLOODING AS WELL AS FLOODING OF LOW LYING AREAS. SMALL STREAMS AND CREEKS IN THE AREA MAY QUICKLY RISE TO BANKFULL AS THE STORM PASSES. HAYES
The radar
The Portland,ME radar (KGYX), 132 km away, was scanning. The volume nearest the first event began at 06:32 UTC.
Event by event
1 flash flood. Local standard time, as filed.
What these are
- Flash Flood
- Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Hail and Damaging Winds in Texas, August 12, 2003
- Wildfire in Montana, August 12 to 24, 2003
- Flash Flooding in Massachusetts, August 12, 2003
- Flash Flood in New York, August 12, 2003
- Wildfire in Hawaii, August 12 to 17, 2003
- Hail and Damaging Winds in Mississippi, August 12, 2003
- Lightning Strike in Virginia, August 12, 2003
- Flash Flood and Flooding in Ohio, August 12, 2003
- Marine Thunderstorm Winds in Lake Erie, August 12, 2003
- Hail and Damaging Winds in Oklahoma, August 12, 2003
- Damaging Winds in Delaware, August 12, 2003
- Hail and Damaging Wind in Texas, August 12, 2003
More
Every storm in New Hampshire in 2003Every state in 2003This day in weather historyWarnings in New Hampshire, August 2003
Sources
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: 5333540.