Locally Heavy Rainfall for the Carolinas; Thunderstorms and Fire Weather Concerns for Intermountain West

Heavy rainfall from scattered thunderstorms is expected across the Southwest, Intermountain West, and Plains. Isolated dry thunderstorms may initiate additional fires across the west. The coastal Carolinas may experience flash floods in the coming days due to repeated thunderstorms. Additionally, a wave of intense summer heat will hit the Southern Plains and central Gulf Coast States this week. Read More >

Overview

A line of severe thunderstorms developed across south central South Dakota late in the evening on September 16 and moved across southeastern South Dakota and into northwestern Iowa and southwestern Minnesota. Wind gusts of 60 to 80 mph were reported across the region. The worst damage was reported around Humboldt, South Dakota and Sheldon, Iowa.


Radar loop of severe thunderstorms moves across eastern South Dakota into western Minnesota and Iowa on September 16-17.	Satellite loop showing severe thunderstorms move from South Dakota into Minnesota and Iowa. The yellow and orange colors and the coldest cloud tops and where the heaviest rain would be located.

Wind
Radar
Storm Reports

Wind

Damaging winds with gusts of 60 to 80 mph moved across portions of southeastern South Dakota into southwestern Minnesota and northwestern Iowa. The most significant damage was around Humboldt and Hartford, South Dakota - located west of Sioux Falls. Numerous trees and power lines were downed by the damaging winds. A few buildings and grain bins were also damaged by the winds. Significant damage also occurred around Sheldon, Iowa where a roof was torn off of a strip mall. There were also numerous reports of trees and large branches snapped across the area.


A large tree down on a house in Humboldt. Photo is courtesy of Minnehaha County Sheriff's Department.	A grain bin was damaged in Humboldt by strong winds just before midnight. Photo is courtesy of Minnehaha Sheriff's Department.

A large tree toppled by the damaging winds has landed on a roof in Hartford, South Dakota. Photo is courtesy of the Minnehaha County Sheriff's Department	Damage to the roof of a building in Hartford, South Dakota associated with damaging winds that moved through Hartford around 12:05 AM 17 September. Photo is courtesy of the Minnehaha County Sheriff's Department.

Radar


The outflow boundary reached Humboldt, SD at 11:55 PM CDT. The strongest winds and damage occurred just behind this boundary. The rain did not reach Humboldt for another 15 minutes	The outflow boundary has moved into Hartford, SD at 12:05 AM CDT. Several large branches and a few trees were knocked down by the strong winds.

Storm Reports

Time and Date	County	Location	State	Type of event	Magnitude	Remarks
10:27 PM 16 Sep 2021	Gregory	Burke	SD	Hail	0.75 in	The hail was accompanied by strong winds, but no damage.
10:27 PM 16 Sep 2021	Gregory	4 W Herrick	SD	Hail	1.25 in
10:48 PM 16 Sep 2021	Gregory	Bonesteel	SD	Hail	0.70 in	Relayed report from a deputy reporting dime sized hail.
11:16 PM 16 Sep 2021	Gregory	2 WSW Pickstown	SD	Thunderstorm Wind Gust	81 mph	South Dakota RWIS station 244 sd on Fort Randall Dam.
11:20 PM 16 Sep 2021	Charles Mix	3 W Geddes	SD	Thunderstorm Wind Gust	63 mph	RAWS station RLAS2.
11:26 PM 16 Sep 2021	Miner	1 W Howard	SD	Thunderstorm Wind Gust	59 mph	South Dakota RWIS station 297 at the junction of SD Hwy 35 and SD Hwy 25.
11:36 PM 16 Sep 2021	Hanson	4 ENE Alexandria	SD	Thunderstorm Wind Gust	64 mph	South Dakota RWIS station 213.
11:36 PM 16 Sep 2021	Hutchinson	2 NW Tripp	SD	Thunderstorm Wind Gust	73 mph	South Dakota RWIS station 26.
11:43 PM 16 Sep 2021	Bon Homme	1 E Tyndall	SD	Thunderstorm Wind Damage	Unknown	Branches down in Tyndall including an 8 inch diameter branch on the east side of town.
11:56 PM 16 Sep 2021	Mccook	3 SE Montrose	SD	Thunderstorm Wind Gust	77 mph	South Dakota RWIS station 18.
11:58 PM 16 Sep 2021	Minnehaha	Humboldt	SD	Thunderstorm Wind Damage	Unknown	Spotter sent pictures of multiple damaged trees and blown over utility trailers.
11:58 PM 16 Sep 2021	Minnehaha	Humboldt	SD	Thunderstorm Wind Damage	Unknown	Spotter sent pictures of the elevator grain bin damage.
11:58 PM 16 Sep 2021	Minnehaha	Humboldt	SD	Thunderstorm Wind Damage	Unknown	Relayed report of high winds leading to transformers blown, with power outages being reported across the area.
12:04 AM 17 Sep 2021	Moody	10 SSW Aurora	SD	Thunderstorm Wind Gust	62 mph	South Dakota RWIS station 224.
12:12 AM 17 Sep 2021	Minnehaha	Crooks	SD	Thunderstorm Wind Damage	Unknown	Several rows of shingles blown off of the house and garage. A neighbor also had large tree blown down in the front yard.
12:15 AM 17 Sep 2021	Yankton	2 NE Yankton	SD	Thunderstorm Wind Gust	63 mph	AWOS at Yankton Municipal Airport.
12:15 AM 17 Sep 2021	Minnehaha	3 SE Baltic	SD	Thunderstorm Wind Gust	73 mph	SDSU mesonet station BTCS2.
12:19 AM 17 Sep 2021	Minnehaha	4 S Colton	SD	Thunderstorm Wind Damage	Unknown	Report from mping: 1-inch tree limbs broken; shingles blown off.
12:20 AM 17 Sep 2021	Moody	10 SSW Aurora	SD	Thunderstorm Wind Gust	64 mph	South Dakota RWIS station 224.
12:28 AM 17 Sep 2021	Union	3 SSW Beresford	SD	Thunderstorm Wind Gust	63 mph	South Dakota RWIS station 16.
12:30 AM 17 Sep 2021	Pipestone	1 NNW Pipestone	MN	Thunderstorm Wind Gust	60 mph	RAWS station RPPM5 (Redstone).
12:37 AM 17 Sep 2021	Rock	1 WSW Beaver Creek	MN	Thunderstorm Wind Gust	59 mph	Minneosta RWIS station MN006.
12:38 AM 17 Sep 2021	Clay	6 E Vermillion	SD	Thunderstorm Wind Gust	71 mph	Measured by a personal weather station.
12:39 AM 17 Sep 2021	Lincoln	5 SSW Worthing	SD	Thunderstorm Wind Gust	58 mph	South Dakota RWIS station 176.
12:39 AM 17 Sep 2021	Union	3 SSW Beresford	SD	Thunderstorm Wind Gust	63 mph	South Dakota RWIS station 16.
12:47 AM 17 Sep 2021	Murray	5 SSE Woodstock	MN	Thunderstorm Wind Damage	Unknown	Uprooted and snapped trees.
12:48 AM 17 Sep 2021	Murray	4 SW Chandler	MN	Thunderstorm Wind Damage	Unknown	A hoop barn was destroyed. The doors are missing on machine shed and roof ripped off.
12:50 AM 17 Sep 2021	Sioux	1 SSW Hawarden	IA	Thunderstorm Wind Gust	63 mph	Mesonet station FW6302.
12:52 AM 17 Sep 2021	Murray	2 E Lake Wilson	MN	Thunderstorm Wind Damage	Unknown	A hoop barn was damaged.
1:07 AM 17 Sep 2021	Sioux	2 NE Maurice	IA	Thunderstorm Wind Gust	63 mph	AWOS at Sioux County Airport.
1:20 AM 17 Sep 2021	Cottonwood	9 N Jeffers	MN	Thunderstorm Wind Damage	Unknown	Crops were blown over.
1:20 AM 17 Sep 2021	Nobles	2 ENE Worthington	MN	Thunderstorm Wind Gust	52 mph	AWOS observations from Worthington Airport.
1:26 AM 17 Sep 2021	O'Brien	3 NNE Sheldon	IA	Thunderstorm Wind Gust	64 mph	AWOS observation from Sheldon Airport.
1:33 AM 17 Sep 2021	Sioux	1 SW Boyden	IA	Thunderstorm Wind Damage	Unknown	Power lines down.
1:33 AM 17 Sep 2021	Sioux	Hull	IA	Thunderstorm Wind Damage	Unknown	A large construction shed was lifted and collapsed in a nearby corn field.
1:34 AM 17 Sep 2021	Sioux	Boyden	IA	Thunderstorm Wind Damage	Unknown	A school bus garage was heavily damaged.
1:34 AM 17 Sep 2021	Sioux	Boyden	IA	Thunderstorm Wind Damage	Unknown	Large tree branches down.
1:40 AM 17 Sep 2021	Jackson	Lakefield	MN	Thunderstorm Wind Damage	Unknown	Trees down from damaging winds.
1:45 AM 17 Sep 2021	O'Brien	5 NW Sanborn	IA	Thunderstorm Wind Damage	Unknown	Large tree limbs down.
1:47 AM 17 Sep 2021	Cottonwood	Mountain Lake	MN	Thunderstorm Wind Damage	Unknown	Several 3-4 inch diameter branches downed.
1:53 AM 17 Sep 2021	Jackson	1 ENE Jackson	MN	Thunderstorm Wind Gust	51 mph	AWOS station at Jackson Airport.
2:04 AM 17 Sep 2021	Clay	4 WNW Spencer	IA	Thunderstorm Wind Gust	54 mph	ASOS station at Spencer Municipal Airport.