Power Outage in Sioux Falls, SD

During several periods over three days with wind chill below -35, values reached a minimum of -46 near Dell Rapids, -43 at Baltic and Colton, and -42 at Sioux Falls. Brandon Valley high school students were forced to move into the gymnasium and other windowless rooms to maintain warmth when a rolling blackout caused a power outage for several hours.

Light freezing drizzle started prior to sunrise and continued through the morning. Ice accumulation on elevated surfaces reached upward of two tenths of an inch, with lesser ice also accumulating on roads and bridges which produced dangerous conditions for several hours. Brief power outages occurred during the early morning hours to over 4000 customers.

Initial damage to a few power poles occurred as the tornado touched down at the intersection of 85th Street and Western Avenue in far southern portions of the Sioux Falls metro area. The tornado tracked northeast for a quarter mile causing tree damage in a residential area before turning more northerly. The tornadic path was evident by scouring vegetation while moving through a wetland area, tossing a trampoline, and causing tree damage to adjacent residences. As the tornado entered a residential area on the north end of the wetlands, more significant damage occurred to several single family residences, with loss of significant sections of roofs and walls, as well as numerous uprooted large trees. At this point, the tornado turned northeast for the last quarter mile of its path, moving along La Quinta Street. Two homes incurred more substantial damage with loss of exterior walls. The tornado lifted before reaching Venita Avenue. Average path width was estimated at 40 yards. Property damage costs are rough estimates.

Ice accumulation and near blizzard conditions led to a shutdown of government offices and schools, and travel was not recommended due to the extremely hazardous conditions. Interstate 90 was closed from Sioux Falls westward, and Interstate 29 was closed from Sioux Falls northward from the evening of April 10 through noon on April 12. A period of freezing rain, sleet and snow resulted in ice accumulations starting the afternoon of April 10 through early April 11 of one-half to three-quarters of an inch. As winds increased and gusted as high as 59 mph at Sioux Falls, widespread power outages resulted as power poles snapped and transmission lines were downed.|Up to 10,000 customers around Sioux Falls were without power at times between the evening of April 10 and April 12, as well as the communities of Humboldt and Hartford where warming shelters were established by local government. Property damage costs include damage to utilities. ||Storm-total snowfall from 2 to 7 inches occurred, with 6.5 inches at Wall Lake, 6.0 inches at Colton, 5.2 inches at the Sioux Falls Airport and 3.8 inches near Garretson. Many areas had snow drifts of several feet, making roads impassable.

Trees down and power out around Cherry Rock Park.

Freezing rain and freezing drizzle of less than 0.05 inch caused icy roads, and accumulated lightly on trees, power lines, and other surfaces. Law enforcement agencies reported a few vehicles accidents on the ice, but no known injuries, with traffic being light because of the holiday.

High winds from a westerly direction followed a low pressure system which had brought Christmas Day rain and thunderstorms. There were several reports of power lines and branches down and resulting power outages, including at least one thousand customers without power for most of Christmas night. Traffic lights and some signs were damaged. Damage also included soffit on the outside of the city's events center. The winds included measured sustained winds of 40 mph measured at Sioux Falls, and a peak gust of 57 mph at measured at Garretson.

Westerly winds behind a cold front reach sustained speed of 40 to 45 mph for a few hours. A gust to 60 mph was measured at Sioux Falls Airport. The high winds caused spotty power line and traffic light damage, especially in Sioux Falls.

An extended period of precipitation began with freezing rain quickly producing heavy ice accumulations, ranging up to more than a half inch in Sioux Falls. The precipitation then changed to sleet and then snow, with sleet and snow accumulations reaching 10 inches near Wall Lake. Very many branches, limbs, whole trees, and power lines were downed by the weight of ice and accompanying wind. Both the Sioux Falls area and other urban areas and rural electric cooperatives suffered major power line damage.|Trees and tree debris blocked many roads, and damaged several vehicles and homes. Major power outages were reported, affecting tens of thousands of people. The winter precipitation made travel impossible in many areas, resulting in schools and businesses being forced to close.

Thunderstorm winds blew down power lines.

Thunderstorm winds blew down power lines and caused tree damage.

Thunderstorm winds blew down power poles.

Thunderstorm winds snapped a power pole at the intersection of Interstate 229 and Benson Road.

Thunderstorm winds caused widespread damage in the Sioux Falls area. Wood and siding were blown off a new house and a nearby fence was blown over. The winds caused tree damage, including 2 to 3 foot diameter trees blown down. Debris from the tree damage blocked several roads. Garages were blown off three homes which were next to each other, and other nearby homes suffered significant damage in an area on West Eli Court which was subjected to the strongest winds, estimated at 100 mph. Windows were blown out in several of these homes, and a large camper was overturned in the same area. A wind gust of 74 mph was measured elsewhere in the city. The winds blew down out power lines in parts of the city.

Thunderstorm winds caused widespread damage in the Sioux Falls area. Wood and siding were blown off a new house and a nearby fence was blown over. The winds caused tree damage, including 2 to 3 foot diameter trees blown down. Debris from the tree damage blocked several roads. Garages were blown off three homes which were next to each other, and other nearby homes suffered significant damage in an area on West Eli Court which was subjected to the strongest winds, estimated at 100 mph. Windows were blown out in several of these homes, and a large camper was overturned in the same area. A wind gust of 74 mph was measured elsewhere in the city. The winds blew down out power lines in parts of the city.

Thunderstorm winds blew down trees and power lines, and damaged power poles.

Snow accumulating 5 to 8 inches was accompanied by north to northeast winds gusting to around 40 mph. The combination resulted in visibilities frequently lowering to a quarter mile or less and, along with drifting snow, made travel difficult to impossible. Power outages were reported from snow weighting down power lines, and snow laden trees falling on lines.

Thunderstorm winds flipped two airplanes, destroying one and causing fuel spills. The winds also tore part of a wall from an aircraft maintenance building. The winds caused tree damage, including large trees blown down, one of which severely damaged the roof of a house. Other tree debris damaged vehicles. Power lines and some poles were blown down, causing power outages.

Thunderstorm winds caused tree damage. The winds also blew down a few power lines, with resulting power outages affecting parts of Sioux Falls. The amount of damage was not known.

Thunderstorm winds caused tree damage, including one tree which fell on a power line, causing a power outage.

Thunderstorm winds caused tree and power line damage. One large tree severely damaged a moving car when it was blown over.

Thunderstorm winds caused power line and tree damage, including 12 inch diameter tree limbs down.

The first phase of a large and long-duration winter storm brought strong warming aloft atop a deep cold layer. With areas of freezing rain and drizzle, significant ice accumulations spread across portions of southeast South Dakota. Spotty minor power outages and broken tree limbs were reported.

A cluster of thunderstorms developed across eastern Montana and the western Dakotas during the morning hours. These storms organized and turned southeastward, feeding on rich inflow of post-frontal air with up to 3000 J/kg of MLCAPE and over 1000 J/kg of DCAPE. Along with strong storm-relative shear, parameters favored development of a strong cold pool and balanced mesocyclone, which spread southeast with the cluster and developed a strong and long-duration severe wind event which traversed South Dakota, southwest Minnesota, extreme northeast Nebraska, and northwest Iowa during the afternoon and early evening. The storm was classified as a derecho, and featured numerous wind gusts from 70 to 100 mph and considerable damage to trees, crops, powerlines, and structures along its path. In some cases, severe wind gusts persisted for more than 30 minutes.

A volatile environment featured a warm front from parts of east central South Dakota into western Minnesota, with a dryline extending to the southwest into Nebraska. With a very strong wave moving northeast through Nebraska into a highly unstable and highly sheared environment, scattered storms initiated and quickly grew upscale to a broad linear structure with damaging winds. With crop development well behind schedule and many fields yet to be planted, there was ample dirt available to be lofted into the leading edge of the storms, which took on the characteristics of a haboob reducing visibility to near zero at the onset of high winds.||A broad swath of winds from 70 to 100 mph devastated much of southeast South Dakota, and portions of southwest Minnesota, northeast Nebraska and northwest Iowa, causing extensive tree and structural damage and scores of injuries. The highest observed wind gust was 107 mph near Tripp, SD. In addition, vehicles and high profile vehicles were blown off several roads, shutting down traffic on Interstates 29 and 90. Two (direct) fatalities occurred in vehicles impacted by debris as the storms moved into the Sioux Falls area. Power was disrupted in a widespread area, with estimates of over 45,000 customers impacted at one time. Many schools were closed due to damage and power issues. The South Dakota Governor requested and was granted a Presidential Disaster Declaration for damage to public infrastructure at an estimated cost of 6.7 million dollars across 20 counties and two reservations. Private losses were a much higher toll, and just one of the impacted counties (McCook) estimated at least 150 to 175 million dollars in damage. Presidential Disaster Declarations were also granted in Dixon County, Nebraska and Lincoln County, Minnesota. ||Following the afternoon line of storms, a secondary band of storms developed near the core of the upper level jet across eastern Nebraska in the early evening hours. These storms also quickly become severe, with a mix of large hail, damaging wind, and even an isolated tornado near Sioux City. This cluster of storms moved through far southeast South Dakota, northwest Iowa and southwest Minnesota during the evening.

A massive arctic plunge into the Northern Plains brought almost a week of dangerous and life threatening wind chills to the region. The worst conditions were recorded between February 13 and February 16 when wind chills occasionally dropped as low as 35 below to 55 below zero. Numerous record low maximum and minimum temperatures were also established. The areal extent of the extreme cold in the central portions of the U.S. led to stress on the power grid, which necessitated several short-term rolling power outages impacting more than 10,000 customers during the peak of the cold.

Elevated instability from 1000-2000 J/kg along with 40-50 kt deep-layer shear sustained organized convection pushing though southeast South Dakota, southwest Minnesota and northwest Iowa. Winds averaged from 60 to 80 mph along the path of the large scale bow echo, producing significant damage to trees and power lines, and minor damage to buildings along the path.

A historic late-season, multi-day winter storm developed rapidly across the central Plains on Wednesday, April 10. This system spiraled several periods of wintry precipitation through the region. The leading precipitation on April 10 was a mix of rain, freezing rain and sleet from far eastern South Dakota through the Interstate 90 areas of southwest Minnesota and northwest Iowa, changing to snow to the north and west. There were even a few elevated thunderstorms which occurred overnight on April 10-11 and produced some near severe hail, which actually occurred after some initial wintry precipitation. Significant icing was centered around 30 miles either side of the Interstate 90 corridor, with as much as a third to three-quarters inch ice accumulation.||Heavy snowfall developed from the early morning of April 11 and continued into the early morning of April 12 across much of southeast South Dakota into northern portions of southwest Minnesota, which accumulated to 1 to 2 feet during the storm. The most persistent snowfall occurred for areas west to north of Sioux Falls, but even there, a brief period of freezing rain or sleet occurred at some point ahead of the main upper trough passage.||The other aspect of this storm was the intense winds, which gusted at the peak from 40 to 60 mph, producing widespread blizzard conditions to southeast South Dakota and southwest Minnesota. Considerable power outages occurred as transmission lines succumbed to the ice accumulation and wind. At the peak, electric companies and cooperatives estimated as many as 25,000 customers were without power. Many areas were without power for a day or two due to the intensity of the storm. The strong winds lofted dust from the Texas/Oklahoma panhandles which caused some of the snowfall toward the latter portions of the event to fall with a brownish color.

Rainfall of one to three inches on frozen ground and into a snow pack with between 2 and 5 inches of liquid water equivalent resulted in considerable overland flooding.||One of the hardest hit areas was around Yankton, where a No Travel Advisory was issued for the city on March 13-14. Businesses along north Highway 81 toward Yankton Mall had considerable ponding of water. Water rescues were necessary as cars stalled in high water in low spots around Yankton. Two people were also rescued from their inundated vehicle on Jim River Road east of Yankton. Water also got into power substations and caused spotty power outages and necessitated temporary evacuation of residents.||State government offices across the area were closed on March 14 due to the flooding.

Freezing rain produced ice accumulations of up to two tenths of an inch in far southeast South Dakota, roughly near and southeast of a Yankton to Sioux Falls line. The icing occurred from a few hours after midnight through the daytime hours. There was widespread icing on roads and other surfaces. The impact of the icing was fairly limited for several reasons. Traffic was very limited because the day was a holiday, and because some businesses closings and activity cancellations were announced ahead of the storm in the southeast corner of the state. Winds remained light, preventing significant damage to trees and power lines. There were several vehicle accidents, but they were not numerous in any given area.

Heavy precipitation with rapid cooling produced a combination of freezing rain, sleet, and snow over all of southeast South Dakota from the early morning hours of April 9th, to the morning of April 11th. Moderate to heavy ice accumulations were reported near Interstate 90. These were followed by moderate to heavy snow and sleet accumulations, mainly near and north of Interstate 90. The ice accumulations, greater than a half inch in some areas, caused major tree and power line damage in the ice storm area. Fallen branches and limbs were numerous, trees were destroyed, roads were blocked, and some vehicles and homes suffered damages from the falling trees, limbs, and branches. There were also major power outages because of the power line and power pole damage. Strong winds with and following the storm, not strong enough to cause significant damage under dry conditions, contributed greatly to the tree and power line damage. The snow and sleet accumulations made travel difficult, especially in areas where downed trees and power lines were already causing road blockages.

Freezing rain produced ice accumulations around a quarter inch or a little more in Union County in extreme southeast South Dakota. Travel and walking were made extremely hazardous, and power lines and trees were damaged. Lesser ice accumulations were reported to the north and west, to the Sioux Falls and Yankton areas, producing slippery conditions in those areas.

Snow, producing accumulations ranging from light to heavy, was accompanied by winds gusting over 40 mph. The snow began early on March 1st after a brief respite from the previous snowfall, with winds increasing as the day went on. Blizzard conditions with widespread near zero visibility in snow and blowing snow resulted. Roads were blocked by drifting and travel was made impossible or extremely difficult. Numerous businesses and schools were forced to close, and school athletic events and other activities were cancelled. Of those who did attempt to travel during the storm, several vehicles were stranded and others slid off roads. There were a few reports of power outages. The blizzard followed another significant snow 1 to 2 days before, so even the areas with light additional accumulations suffered the blizzard conditions. The snow decreased on the night of March 2nd, with blizzard conditions abating by early morning on March 3rd. The heavier new snow accumulations of 8 to 12 inches were from Sioux Falls and Salem north to Brookings and De Smet. The lighter accumulations of 1 to 3 inches were near the Missouri River from Vermillion and Yankton west to Pickstown and Gregory.

Snowfall of 4 to 8 inches was accompanied by increasing winds which gusted to around 35 mph. The winds caused low visibilities in blowing snow during the latter part of the snowfall. Drifting snow also added to travel problems. The wet snow and winds combined to bring down power lines, causing a significant power outage in the Freeman area. Numerous schools cancelled or delayed classes for a day, and some businesses also closed.

Snowfall varying from 4 to 15 inches combined with winds gusting over 50 mph to produce blizzard conditions. The heaviest snowfalls were mostly near and west of the James River, in the area where a severe ice storm immediately preceded the blizzard. Several reports of 6 to 8 foot drifts were received from this area. Visibilities were lowered frequently to zero and travel was made impossible in many areas. Roads, including Interstate Highways 90 and 29 were closed for extended periods of time. Most schools and businesses that were not already closed because of the ice storm were forced to close. The winds during the blizzard continued to bring down power lines and poles, most of which had been coated and weighted down by ice in the area hit by the ice storm. In addition, minor damage was caused to homes and vehicles by the strong winds and by wind blown debris, mainly from trees. A 79 year old man died from exposure three and a half miles north of Harrison in Douglas County when he became stuck in a barbed wire fence after the tractor he was driving on his farm became entangled in the fence late on the afternoon of the 28th.

Sustained winds of 40 to 45 mph with gusts above 60 mph persisted from mid morning until late afternoon. The winds caused widespread tree damage with branches and smaller tree debris broken off. Several power lines were knocked down by the wind or by wind blown debris. This resulted in several power outages, especially between the Missouri and James Rivers. Damages to buildings was mostly to shingles and gutters. However, a metal storage building was blown over at Mitchell. Also at Mitchell, construction barriers were blown over, and windows were broken in two vehicles by blowing rocks. An aluminum recycling cage was blown away at Woonsocket. A window was blown out at a school in Freeman. In Sioux Falls, there was damage to the airport tower.

Wet snow accumulated 6 to 10 inches. The snowfall caused travel and event delays, with many school systems either delaying or cancelling classes on Monday the 7th. The snowfall contributed to several accidents. A few power lines were reported down because of the weight of the snow.

Freezing rain was followed by snowfall of 3 to 7 inches. The combination caused numerous minor accidents and several event cancellations, as well as early school closings. The ice and snow brought down some power lines, particularly in the Dell Rapids area where power outages were reported. Power outages were also reported in the Huron area, where ice and snow accumulation caused power lines to slap together in the winds, triggering circuit breakers.

Widespread heavy snow was preceded by freezing rain. Precipitation from the Chamberlain to Huron areas and east to Brookings was mainly snow, with accumulations ranging from 8 inches in several areas to 19 inches at Huron. The heavy snow on top of the ice made travel difficult, and in places impossible, as some roads were blocked. Cattle losses were suspected from the heavy wet snow occurring during calving season, but in most cases specific numbers were not available. Over the Southeast part of the affected area, including near and just south of Sioux Falls, damage to power lines due to icing was reported, with several power outages in Sioux Falls. Three to six inches of snow fell on top of the ice in this area.

Freezing rain was followed by snow and blowing snow. Heavy snow fell over much of the area. New snow accumulations were 8 inches or more from Brookings west to Huron...and southwest to Mitchell, Chamberlain, Burke, and Pickstown. The greatest reported accumulation was 15 inches at Burke. Along and southeast of a Sioux Falls to Yankton line, new snow accumulations were in the 2 to 6 inch range, but significant icing occurred in this area. There were scattered reports of tree and power line damage, and of minor structural damage due to the weight of the snow, but no damage estimates were available. Winds gusting to 40 to 50 mph during and after the snowfall caused near blizzard conditions and considerable drifting, blocking roads and stranding numerous vehicles. Travel was impossible in many areas and many businesses, colleges, and technical schools were closed. Interstate highway 90 and parts of Interstate highway 29 were closed for more than 18 hours due to the drifting snow and poor visibilities. County and State snowplows were pulled off the roads until conditions improved.

Freezing rain caused significant ice accumulation on trees, power lines, and other exposed surfaces, although ice accumulation on roads was slight due to warm surfaces. The ice caused tree damage, much of it minor, but in some areas such as Tyndall, limbs and large branches were broken. A few power lines and poles were also pulled down by the weight of the ice.

High winds with sustained speeds of 40 to 50 mph and gusts above 60 mph persisted from around noon into early evening. Numerous shingles were blown off of roofs. Some power lines were blown down with resulting outages, most notable in Beadle County including Huron. Several empty mobile homes were rolled over at a lot near Sioux Falls. The winds exacerbated numerous grass fires, a few of which also burned farm buildings. One firefighter suffered exhaustion and smoke inhallation while fighting a fire on the northeast edge of Sioux Falls.