A strong atmospheric river moving into northern California later today will bring a threat for moderate to heavy rainfall and flooding, gusty to high winds, and mountain snows for parts of the Northwest U.S. through Wednesday. Gusty winds and isolated showers are expected today in the Northeast U.S. behind a cold front. Wind Advisories have been issued. Read More >
Overview
Two days of severe weather affected northeastern Wyoming and western South Dakota on June 1–2, 2015. Large hail, damaging winds, and flooding were reported. Both storms were captured on time-lapse video by off-duty NWS employees. Pictures of the flooding aftermath and giant hail are included.
Photos & Video
Storm from June 1, 2015
| Time-lapse video taken by Dan McKemy (off-duty NWS employee) near Black Hawk, SD, on June 1, 2015 | Time-lapse video taken by Aaron Ward (off-duty NWS employee) near Rapid City, SD, on June 1, 2015 |
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| Hail near Piedmont, SD, around 7 pm MDT June 1, 2015 (photo by off-duty NWS employee Alex Calderon) |
These photos were taken during the early morning of June 2, 2015 by off-duty NWS employee Alex Calderon.
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Storm from June 2, 2015
A series of severe thunderstorms affected northeastern Wyoming and western South Dakota between 4 pm June 2, 2015 and the early morning of June 3, 2015. Up to golf ball size hail was reported along with wind gusts up to 70 mph. The time-lapse of the storm below was the one that produced golf ball size hail around 4:30 pm MDT 4 miles northeast of Rockerville, SD. The video is indicative of a low precipitation (LP) supercell during the initial stages of the thunderstorm.
| Time-lapse video taken by Dan McKemy (off-duty NWS employee) near Rapid City, SD, on June 2, 2015 |
Radar
June 1, 2015
A severe thunderstorm developed between Sturgis and Rapid City, SD, around 5:10 pm MDT on June 1, 2015. The storm moved very slowly to the south producing hail up to softball size in Piedmont, SD, around 6:55 pm. The storm weakened by 9 pm, but flooding continued overnight. Here are two radar images from 6:38 pm MDT when the storm was very intense.
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| June 1, 2015 6:37 pm MDT 0.5 base reflectivity image | June 1, 2015 6:37 pm MDT 0.5 3-dimensional view of supercell |
Storm Reports
Storms Reports for June 1, 2015
THE STORM REPORTS LISTED BELOW ARE IN DESCENDING ORDER AND MAY NOT NECESSARILY
BE THE FINAL STORM REPORTS.
HAIL REPORTS LISTED BY SIZE (INCHES)
SIZE LOCATION ST COUNTY TIME
------ ----------------------- -- -------------- -------
4.50 PIEDMONT SD MEADE 0655 PM
2.50 1 NW PIEDMONT SD MEADE 0712 PM
2.50 PIEDMONT SD MEADE 0655 PM
MILE MARKER 44 ON I90
2.00 1 NW PIEDMONT SD MEADE 0620 PM
1.75 1 ESE PIEDMONT SD MEADE 0735 PM
1.75 BLACK HAWK SD MEADE 0717 PM
1.75 PIEDMONT SD MEADE 0655 PM
1.75 2 S TILFORD SD MEADE 0520 PM
1.50 1 NW PIEDMONT SD MEADE 0613 PM
1.25 1 NW PIEDMONT SD MEADE 0550 PM
1.25 TILFORD SD MEADE 0510 PM
1.00 7 E CREIGHTON SD PENNINGTON 0943 PM
1.00 3 N DOWNTOWN BELLE FOUR SD BUTTE 0922 PM
1.00 PIEDMONT SD MEADE 0626 PM
EXIT 44 AND I-90 LOTS OF HAIL
1.00 PIEDMONT SD MEADE 0619 PM
HEAVY RAIN... SOME STREETS OVERFLOWING WATER
PONDING INTO GRASSY AREAS
0.88 11 NW DOWNTOWN RAPID CI SD MEADE 0816 PM
OVER AN INCH OF RAIN
0.25 1 NW PIEDMONT SD MEADE 0550 PM
TSTM WIND REPORTS LISTED BY SPEED (MPH)
SPEED LOCATION ST COUNTY TIME
------ ----------------------- -- -------------- -------
65.00 2 NNW SAINT ONGE SD LAWRENCE 1000 PM
60.00 9 N BOX ELDER SD MEADE 0800 PM
Storms Reports for June 2, 2015
THE STORM REPORTS LISTED BELOW ARE IN DESCENDING ORDER AND MAY NOT NECESSARILY
BE THE FINAL STORM REPORTS.
HAIL REPORTS LISTED BY SIZE (INCHES)
SIZE LOCATION ST COUNTY TIME
------ ----------------------- -- -------------- -------
1.75 3 N ROCKERVILLE SD PENNINGTON 0432 PM
1.75 4 NE ROCKERVILLE SD PENNINGTON 0430 PM
1.25 4 NE ROCKERVILLE SD PENNINGTON 0430 PM
1.00 4 S DOWNTOWN RAPID CITY SD PENNINGTON 0436 PM
0.88 ROCKERVILLE SD PENNINGTON 0620 PM
0.88 ROCKERVILLE SD PENNINGTON 0442 PM
0.75 3 N SHERIDAN LAKE SD PENNINGTON 0415 PM
TSTM WIND REPORTS LISTED BY SPEED (MPH)
SPEED LOCATION ST COUNTY TIME
------ ----------------------- -- -------------- -------
70.00 9 ENE BELVIDERE SD JACKSON 1230 AM (JUNE 3, 2015)
66.00 1 NE MIDLAND SD HAAKON 1230 AM (JUNE 3, 2015)
62.00 10 ESE PINE HAVEN WY CROOK 0825 PM
62 MPH WIND GUSTS FROM 825 TO 830 PM.
60.00 3 WNW WASTA SD PENNINGTON 1050 PM
60.00 1 E DOWNTOWN RAPID CITY SD PENNINGTON 1008 PM
60.00 2 ENE WESTON WY CAMPBELL 0735 PM
60.00 1 NW MARTIN SD BENNETT 0715 PM
58.00 6 W PARMELEE SD TODD 0800 PM
58.00 1 ESE MARTIN SD BENNETT 0715 PM
57.00 4 SE SUNDANCE WY CROOK 0850 PM
Environment
June 1, 2015
NWS Rapid City balloon information showed a moderately unstable air mass with sufficient vertical wind shear for slow-moving supercells. The surface map showed dewpoints in the lower 60s on the eastern side of the Black Hills.
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| Sounding for Rapid City at 6 pm MDT 1 June 2015 (00z the 2nd) | Hodograph for Rapid City at 6 pm MDT 1 June 2015 (00z the 2nd) | Surface map valid 7 pm MDT 1 June 2015 |
June 2, 2015
Below is the 6 am balloon information for NWS Rapid City because the afternoon balloon release was not representative. However, this still showed a fairly unstable air mass, and afternoon surface dewpoints were in the upper 50s with a northerly wind. The result on this day was a supercell that formed farther south than the previous day, near Rockerville.
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| Sounding for Rapid City at 6 am MDT 2 June 2015 | Hodograph for Rapid City at 6 am MDT 2 June 2015 | Surface map valid 3 pm MDT 2 June 2015 |
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