Montana, 2016

Strong Wind in Montana, May 12, 2016

May 12, 2016 · NWS MSO · 1 event in 1 county or zone

A backdoor cold front brought strong northerly winds to Flathead Lake during the afternoon and evening hours on May 12th negatively impacting a barge operation off of Finley Point.

Where it happened

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The toll

Deaths
0
Injuries
0
Property damage
$1,000
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 MSO wrote it up.

A backdoor cold front brought strong northerly winds to Flathead Lake during the afternoon and evening hours on May 12th negatively impacting a barge operation off of Finley Point.

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 Missoula, MT wrote its last area forecast discussion before the first event at May 12, 1:36 PM MST, 5 hours 24 minutes earlier.

Area forecast discussion, May 12, 1:36 PM MST, 5 hours 24 minutes before
Area Forecast Discussion
National Weather Service Missoula MT
236 PM MDT THU MAY 12 2016

.DISCUSSION...The atmosphere will be moist and unstable enough to
support a few showers over northwest Montana and along the
Continental Divide into this evening. However, the bigger weather
impact going into this evening is the moderate to strong northeast
winds that will develop across parts of western Montana. The areas
that should see the strongest winds and most impacts should be
Kalispell and Flathead Lake this evening and then Missoula,
Garrison Junction, Deerlodge, and the Bitterroot Valley later
this evening into Friday morning.

In comparison, Grangeville, Orofino, Riggins and other areas of
north central Idaho should see relatively mild and tranquil
conditions this evening and tonight.

The breezy northeast winds should continue across western Montana
Friday. Otherwise dry conditions should prevail Friday and Friday
night across the northern Rockies.

An upper low pressure system will begin to spread moisture/showers
across north central Idaho Saturday afternoon. A few of these
showers may spread into the Missoula area, Bitterroot mountains,
and Sapphire mountains Saturday evening.

The upper low pressure system should then push additional moisture
over north central Idaho and west central/southwest Montana Sunday
and Sunday night. Areas of moderate valley rain can be expected.
Right now it appears the Clearwaters of Idaho may see the heaviest
rain amounts...up to around one inch. There is sufficient cooler
air aloft with this weather system to again support snow in the
higher terrain and mountain passes late Sunday into Monday. Lost
Trail, Bannock, and Williams Summit passes may see additional
snow accumulation and local slick roads.

A rather cool and breezy westerly flow pattern is expected Tuesday
of next week.

In the longer term...there is quite a bit of typical
uncertainty...but it appears the main storm track will remain over
the northern Rockies and usher additional moist weather systems
into the region.

&&

.AVIATION...An unstable atmosphere will support scattered showers
and isolated thunderstorms over northwest Montana and along the
Continental Divide into this evening. Expect brief moderate to
heavy rain with isolated storms. A back door cold front has
already shifted westward into far northwest Montana and will
continue to push south and west across the rest of western Montana
this evening and overnight. This will translate into strong and
gusty east to northeast winds at some airport terminals. KGPI will
be impacted first late this afternoon and evening with the
strongest northeast winds (locally to 40-45 mph). KMSO should see
the gusty northeast winds and then shifting to easterly winds into
Friday morning.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Lake Wind Advisory from 7 PM this evening to 9 AM MDT Friday for
     Flathead Lake in the Flathead/Mission Valleys.

ID...None.
&&

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 strong wind. Local standard time, as filed.

Strong Wind, Flathead/Mission Valleys

When
May 12, 7:00 PM MST to 9:00 PM MST
Where
Flathead/Mission Valleys forecast zone
Measured
43 kt (49 mph) estimated gust
Property damage
$1,000
Reported by
Mesonet
Coordinates
47.872, -114.424 (the zone’s center; the record gives no point)

The Flathead Lake Biological Station Narrows sensor reported an increase in northerly winds gusting to 41 mph at times by 8 pm MDT. Winds could have peaked closer to 50 mph over the open water towards the center of the lake. This northerly wind caused waves to grow over 26 miles of fetch reaching an estimated 6 to 8 feet at times. The waves knocked a shipping container off the stern of the barge and eventually the vessel sank. The bow of the barge was nosed onshore while the stabilizers were extended into the mud. With time, the waves hammered the legs down into the silt over time swamping the barge.

What these are

Strong Wind
Non-thunderstorm winds below high wind criteria that nonetheless caused damage or casualties.

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

The same day elsewhere

More

Every storm in Montana in 2016Every state in 2016This day in weather historyWarnings in Montana, May 2016

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: 635820.