Tornado outbreak of August 8–9, 1993

The tornado outbreak of August 8–9, 1993 was a small tornado outbreak that occurred over the Upper Midwest of the United States for a period of two days. An F0 tornado near Littlefork, Minnesota lifted and moved a mobile home, killing its two occupants. It is Minnesota's most recent single tornado to cause multiple deaths. Other minor tornadoes occurred in Minnesota, Iowa and Wisconsin, causing limited damage.

Tornado outbreak of August 8–9, 1993

Type	Tornado outbreak
Duration	August 8–9, 1993
Tornadoes confirmed	7
Max. rating^1	F2 tornado
Duration of tornado outbreak^2	~ 1 day, 20 hours
Damage	~$1.22 million (tornadic damages only)
Casualties	2 (2 others injured)
^1Most severe tornado damage; see Fujita scale ^2Time from first tornado to last tornado

Meteorological synopsis

At about 6:00 PM CST (23:00 UTC) a sea-level cyclone and occluded front were located over North Dakota.[1] Observations from International Falls showed the tropopause was at 39,800 feet (12,100 m), while observations from Bismarck recorded it at 39,000 feet (12,000 m).[1] Lifted Indices (LI) at the time CDT were also low, and thunderstorms were starting to develop in the Eastern Dakotas.[1] In response to the storms, the National Severe Storms Forecast Center (NSSFC) issued a tornado watch for the eastern Dakotas.[1] At 11:55 PM CST (0440 UTC) the outbreak's first confirmed tornado was reported near Gully, Minnesota. As a result of the tornado a Tornado Warning was issued for Clearwater County; the storm's next location.[1][2] Ten minutes later at 12:05 PM CST (0450 UTC) another tornado, rated an F0, was reported near Roseau, Minnesota.[1][3] After the two August 8th tornadoes, most local warnings were allowed to expire, as local radar did not determine any of the storms to be severe.[1] During the early morning hours of August 9 Duluth radar indicated multicellular convection near the Littlefork, Minnesota area that was associated with an outflow boundary from the earlier Dakota storms.[1] At 1:35 AM CST (0735 UTC) a deadly F0 tornado touched down unexpectedly near Littlefork, in association with the multicellular thunderstorm.[4] Unstable air from the day before persisted over much of the upper Midwest, and allowed storms to form over much of the area. On the night of August 9th the strongest tornado of the outbreak, an F2, occurred near New Hampton injuring 2 people.[5] Another cluster of thunderstorms occurred over Wisconsin, producing 3 relatively minor tornadoes.[6]

Confirmed tornadoes

Confirmed tornadoes by Fujita rating

FU	F0	F1	F2	F3	F4	F5	Total
0	5	1	1	0	0	0	7

August 8 event

List of confirmed tornadoes – August 8, 1993
F#	Location	County	Coord.	Time (UTC)	Path length	Damage
Minnesota
F0	S of Gully	Polk	47.44°N 95.38°W	0440	.10 miles (0.2 km)	Brief touchdown, tornado uprooted trees and damaged some buildings.[2]
F0	N of Roseau	Roseau	48.52°N 95.45°W	0450	.10 miles (0.2 km)	Brief touchdown that damaged a warehouse, total damage $500,000.[3]
Sources: NCDC Storm Events Database tornado list August 8, 1993.[7]

August 9 event

List of confirmed tornadoes – August 9, 1993
F#	Location	County	Coord.	Time (UTC)	Path length	Damage
Iowa
F2	W of New Hampton	Chickasaw County	43.04°N 92.27°W	2240	5 miles (8.0 km)	Injured 2 people and caused $550,000 in damages.[5]
Minnesota
F0	SW of Littlefork	Koochiching	48.24°N 93.28°W	0735	1.25 miles (2.0 km)	2 deaths - see section on this tornado
Wisconsin
F0	SE of Fifield	Price County	45.49°N 90.9°W	0015	.30 miles (0.5 km)	Caused $5,000 in crop damage[8]
F1	E of Phillips	Price County	45.49°N 90.9°W	0100	.50 miles (0.8 km)	The tornado ripped a roof off a barn and uprooted trees causing $55,000 in total damage.[6][9]
F0	N of Tripoli	Oneida County	45.34°N 90.00°W	0115	.30 miles (0.5 km)	Caused limited damage of $500.[9]
Sources: NCDC Storm Events Database tornado list August 9, 1993.[7]

Littlefork tornado

The tornado near Littlefork lifted a mobile home and moved it .25 miles (0.4 km) to the northeast of the original site. The two occupants of the home were killed and the tornado caused $50,000 in damage.[4] National Weather Service officials first believed the tornado to be "straight-line winds", but after an investigation they determined that a tornado had occurred at the site.[10]

References

1. Packingham, Dean. "The Littlefork Tornado: A Post-Event Analysis". National Weather Service Office Duluth. Retrieved 7 March 2010.
2. "Event Record Details". National Climatic Data Center (NCDC). Retrieved 4 March 2010.
3. "Event Record Details". National Climatic Data Center (NCDC). Retrieved 4 March 2010.
4. "Event Record Details". National Climatic Data Center (NCDC). Retrieved 4 March 2010.
5. "Event Record Details". National Climatic Data Center (NCDC). Retrieved 4 March 2010.
6. "Event Record Details". National Climatic Data Center (NCDC). Archived from the original on 13 June 2007. Retrieved 5 March 2010.
7. "Storm Events". National Climatic Data Center (NCDC). Archived from the original on 1 April 2010. Retrieved 2 March 2010.
8. "Event Record Details". National Climatic Data Center (NCDC). Archived from the original on 13 June 2007. Retrieved 5 March 2010.
9. "Event Record Details". National Climatic Data Center (NCDC). Retrieved 5 March 2010.
10. "Couple killed as tornado slams into Minnesota". Duluth News-Tribune. The Spokesman-Review. August 10, 1993. Retrieved 7 March 2010.

External links

• NWS Duluth Summary