Record Rainfall in Sioux Falls, South Dakota
As Jeff Masters blogged today (June 17th)
deadly tornadoes struck Nebraska on Monday June 16th. Tornadoes also were reported in Iowa and Wisconsin. Accompanying the twisters were some phenomenal rainfalls in nearby South Dakota. One site, Canton, reported 8.43” of rainfall in the 24 hours ending at 6 a.m. local time June 17th.Radar estimated rainfall over southeastern South Dakota (and surrounding region) for the 24-hour period of 9 a.m. June 16 to 9 a.m. June 17.
Image from NWS-Sioux Falls.
The 8.43” 24-hour precipitation figure for Canton is just shy of the official South Dakota state record of 8.74” measured at Groton on May 6, 2007. Canton is an official NWS COOP site and much heavier unofficial 24-hour rainfalls have occurred in South Dakota at other locations in the past. Most notably the estimated 15” in about six hours that fell at a site called Nemo along the Box Elder Creek, and 14.5” at Sheridan Lake in the Black Hills on June 9, 1972. This event resulted in the disastrous Black Hills and Rapid City flood that killed 236, the 2nd deadliest flash flood in U.S. history (the Famous Johnstown, Pennsylvania flood of May 31, 1889 being the worst with 2,200 fatalities).
Canton is about 15 miles southeast of Sioux Falls where 3.00” was officially measured at Foss Airfield on June 16th. Of this amount, 0.85” fell in just a five-minute period between 3:05-3:10 p.m. CDT (that’s a rate of 10.2” per hour!). The storm was accompanied by an 87 mph wind gust and hail.The heavy rainfall over the past three days (June 14-16) has resulted in massive flooding across eastern South Dakota and Iowa. Interstate 29 was forced to close south of Sioux Falls for a good portion of the day on Monday. The photo above is ironically dated June 16, 2011 but shows the same section of I-29 under water during the more widespread regional floods that affected the same area exactly five years ago to the day.
Photo from Salvation Army of Siouxland.
The 3.00” in Sioux Falls on June 16th was preceded by 2.74” on June 15th and 1.97” on June 14th, the latter two being daily records. On June 14-15 the city picked up 4.56” in the 24-hour period of 5 a.m., June 14 to 5 a.m., June 15, just shy of the all-time (any month) 24-hour precipitation record of 4.59” set on August 1, 1975. However, the 7.71” from June 14-16 brings the June monthly precipitation total in Sioux Falls to 13.04”. This has crushed the previous all-time monthly record for the city of 9.42” set back in May 1898. Precipitation records for Sioux Falls began in June 1890, although the official POR starts in 1893 (a few days of records are missing from May and June 1891 and also from October 1893).Climate table for Sioux Falls, South Dakota as of June 16th (an additional .07" fell on June 17-18). Note that five days of the month so far have seen 1.00”+ rainfall accumulations. The average June total precipitation for the site is 3.92” (POR 1981-2010).
Table from NWS-Sioux Falls.
What is extraordinary about this month’s record rainfall in Sioux Falls is that there are still 12 days left to the month and yet the previous record has already been surpassed by a margin of 38%, this for a site with 121 years of record!
Christopher C. Burt