Flooding in Montana, May 30 to 31, 2003

Name: Flooding in Montana, May 30 to 31, 2003
Start: 2003-05-30T05:00
End: 2003-05-31T23:59
Location: Montana

May 30 to 31, 2003 · NWS TFX · 3 events in 3 counties and zones

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 3

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 TFX wrote it up.

Due to very warm temperatures over much of Southwest Montana during the last week of May, a significant snow melt began to occur at higher elevations in the mountains of Southwest Montana. By May 30th, the Big Hole, Gallatin, and the Jefferson Rivers all began to overflow their banks. The water did approach some rural roadways, along with flooding of low land pastures next to the river. A few homes were threatened by the rising waters. The rivers continued to rise, cresting during the first week of June.

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 Great Falls, MT wrote its last area forecast discussion before the first event at May 30, 2:02 AM MST, 2 hours 58 minutes earlier.

Area forecast discussion, May 30, 2:02 AM MST, 2 hours 58 minutes before

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
302 AM MDT FRI MAY 30 2003

.DISCUSSION...

TODAY...WILL DROP FLOOD ADVISORY WITH NO SMALL STREAM FLOODING HAVING
BEEN REPORTED AND TEMPERATURES TRENDING DOWNWARD TODAY. RIDGE FINALLY
BREAKS DOWN ALLOWING A MOIST AND UNSETTLED SOUTHWEST FLOW TO
VISIT THE REGION. LIGHT SCATTERED SHOWERS ARE ALREADY ON THE RADAR
IN BEAVERHEAD COUNTY. SHARP SHORTWAVE TROUGH OVER NORTHERN
CALIFORNIA THIS MORNING WILL APPROACH SOUTHWEST MONTANA THIS
AFTERNOON. THE TROUGH WILL ENCOUNTER MOIST AIR AT THE SURFACE AND
STEEP LAPSE RATES ALOFT. THE STORM PREDICTION CENTER HAS TAKEN
NOTICE AND PUT THIS UNDERRATED HOTBED FOR SEVERE WEATHER UNDER A
SLIGHT RISK. MAIN THREAT WILL BE GUSTY WINDS AND HAVE ADDED THIS TO
THE SOUTHWEST ZONES. ALTHOUGH THERE WILL NOT BE MUCH SUN IN THE
SOUTHWEST...THE VIGOROUS TROUGH WILL PROVIDE ENOUGH LIFT TO
POSSIBLY GENERATE 60 MPH T-STORM GUSTS OR EVEN SEVERE HAIL.

TONIGHT...PRECIP COVERAGE WILL PEAK IN THE SOUTHWEST IN THE EARLY
EVENING. TROUGH WILL THEN WEAKEN AS IT CONTINUES NORTHEAST SO HAVE
TRENDED POPS ACCORDINGLY. WILL STILL BE ENOUGH PUNCH LEFT TO BRING
SHOWERS TO CENTRAL ZONES. NOT AS CONFIDENT ABOUT THE NORTHERN ZONES
THOUGH. LATEST ETA RUN HAS INTENSIFIED THIS SYSTEM FURTHER MAKING ME
BELIEVE THAT ANY RAIN THAT DOES FALL SHOULD BE JOINED BY THUNDER.

SATURDAY AND SUNDAY...A DRYING TREND DURING THIS TIME AS UPPER FLOW
VEERS TO THE WEST. THUNDERSTORMS POSSIBLE AGAIN SATURDAY AFTERNOON
AS WEAK COLD FRONT MOVES FROM WEST TO EAST DURING THE AFTERNOON OR
EVENING. SUNDAY MAY GET WINDY ALONG THE ROCKY MOUNTAIN FRONT AS
WESTERLY FLOW INCREASES...INDUCING A LEE SIDE SURFACE TROUGH TO FORM.
POMEROY

MONDAY THROUGH THURSDAY...AN UPPER LEVEL HIGH PRESSURE RIDGE WILL BE
OVER THE WEST COAST ON MONDAY. THIS KEEPS THE ZONES UNDER NORTHWEST
FLOW ALOFT AND WILL CONTINUE TO KEEP TEMPS MODERATE. THE AIRMASS
SHOULD GENERALLY BE NEUTRAL OR STABLE MONDAY AND TUESDAY BUT WILL
KEEP A SLIGHT CHANCE OF SHOWERS UNDER THE NW FLOW. THE AIRMASS
GRADUALLY DRIES AS THE RIDGE MOVES EAST...AND TEMPS WILL GRADUALLY
INCREASE. ZELZER

.CCF NUMBERS
GTF BE 079/051 075/047 074 19253
    BBBBB 044/069 042/068 042/069 043/073 045 20222220000
CTB BE 075/047 071/046 071 19134
    BBBBB 043/066 041/065 041/067 042/070 045 20222220000
HLN BB 086/053 078/047 075 19374
    BBBBB 047/072 044/072 044/072 045/075 046 20222220000
BZN BB 083/048 077/045 076 19343
    BBBBB 040/072 042/068 040/069 041/072 042 30222220000
WEY EB 078/040 069/037 068 19442
    BBBBB 035/064 036/061 035/062 035/066 032 20222220000
DLN EB 083/052 072/045 073 19462
    BBBBB 042/071 043/068 041/068 042/068 042 20222220000
HVR BE 081/050 075/048 079 19022
    BBBBB 047/075 045/071 045/071 045/076 047 30222220000
LWT BE 075/049 072/045 070 19-33
    BBBBB 042/065 041/064 042/064 042/067 043 30222220000

.TFX...FLOOD WARNING FOR THE GALLATIN RIVER NEAR LOGAN THROUGH
SATURDAY MORNING.

Hazardous weather outlook, May 30, 3:44 AM MST, 1 hour 16 minutes before

MTZ008>015-044>055-310010-
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
444 AM MDT FRI MAY 30 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST
MONTANA

.DAY ONE...TODAY

SEVERE THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND EVENING IN
SOUTHWEST MONTANA. A STRONG DISTURBANCE WILL MOVE INTO SOUTHWEST
MONTANA LATE THIS AFTERNOON. THIS WILL CAUSE SHOWERS AND
THUNDERSTORMS TO FORM. SOME STORMS MAY BE SEVERE...MAINLY BETWEEN 4
AND 9 PM...AND SOUTH AND WEST OF A LINE FROM HELENA TO BOZEMAN. THE
PRIMARY THREAT WILL BE WIND GUSTS TO 70 MPH...ALTHOUGH HAIL TO ONE
INCH IN DIAMETER IS ALSO POSSIBLE.

A FLOOD WARNING IS IN EFFECT FOR THE GALLATIN RIVER NEAR LOGAN
THROUGH SATURDAY. REFER TO GTFFLSTFX FOR THE LATEST INFORMATION.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A FLOOD WARNING IS IN EFFECT FOR THE GALLATIN RIVER NEAR LOGAN
THROUGH SATURDAY. REFER TO GTFFLSTFX FOR THE LATEST INFORMATION.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS...INCLUDING DAMAGING WIND GUSTS AND HAIL...TO THE
NATIONAL WEATHER SERVICE.

Event by event

3 flood. Local standard time, as filed.

Flood, Beaverhead

When: May 30, 5:00 AM MST to May 31, 11:59 PM MST
Where: Beaverhead forecast zone
Reported by: EMERGENCY MANAGER

Flood, Madison

When: May 30, 5:00 AM MST to May 31, 11:59 PM MST
Where: Madison forecast zone
Reported by: EMERGENCY MANAGER

Flood, Gallatin

When: May 30, 5:00 AM MST to May 31, 11:59 PM MST
Where: Gallatin forecast zone
Reported by: EMERGENCY MANAGER

What these are

Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Montana in 2003 Every state in 2003 This day in weather history Warnings in Montana, May 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: 5358289, 5358290, 5358291.