March 16, 1999 Wind Event
On the morning of March 16 a strong upper level storm system was moving across the northern Rockies. This storm system was pushing a Pacific air mass into the Northern Plains. At the leading edge of this air mass was a strong cold front that extended from the south of a surface low over eastern Montana. Ahead of the front a strong southwest downslope wind developed that pushed warmer air into northeast Wyoming and western South Dakota. Some of the gusts ahead of the front exceeded 60 mph over northeast Wyoming and 40 mph over western South Dakota. Temperatures rose into the lower 70s and even reached 81 at Winner for a high.
By the early afternoon an area of showers developed along the front as it passed through Billings, Montana. These showers produced rain that fell into a dry air mass behind the front and caused winds to increase dramatically. As the front rolled across southeast Montana, several stations reported gusts to 70 mph. These wind gusts prompted the forecasters in Rapid City to issue a High Wind Warning for northwest South Dakota including Rapid City with the 3:00 PM forecast issuance.
The cold front blasted into northwest South Dakota around 4 PM with winds gusting at Buffalo up to 67 mph. As it continued to roar southeastward, it passed Spearfish and then Sturgis with equal vengeance before 5 PM, and then Rapid City Between 5:05 and 5:15 PM. Its passage was noticed not only by the stiff winds up to 50 mph at the NWS office, but also a thick cloud of dust that was blown up from Pete Lien's cement plant. Street spreadings left over from the recent snows of March 5th and 10th were also blown around . The front continued a steady fast march southeastward through Faith, Wall and Pine Ridge by 6 PM and then into central parts of the South Dakota by 8 PM.
Post analysis indicated that the initial frontal passage contained the strongest winds with gusts of 67 MPH at Buffalo, 61 MPH at Faith and Kadoka, and 72 MPH at Ellsworth Air Force Base.
Below you will find a contour map showing the wind speeds recorded.
