Power Outage in Waukee, IA

Former NWS employee estimated 70 mph winds and reported brief power outage.

Trained spotter reported a large tree limb hit a home, causing the home to lose power.

Trained spotter reported a large tree limb hit a home, causing the home to lose power.

NWS employee reported power poles leaning over halfway to the ground. This is a delayed report.

Emergency manager reported power lines down between Dallas Center and Grimes. Dallas Center without power at the time of the report.

Emergency manager reported power poles blown down on Highway 44, semi truck blownn over at intersection of P46 and Highway 141. All between Perry and Dawson.

Fire department reported powerlines down near the 190th street area of H ave west of Minburn. Time estimated from radar.

Also a power pole was reported snapped due to the strong winds 4 miles west of Minburn. A house window was also reported blown out in Adel.

Trees and power lines down.

Large trees down in Waukee and Woodward. Power out across half of Waukee.

Power lines and trees were damaged as well as farm outbuildings being damaged or destroyed.

A strong upper level low pressure system lifted northeast out of the southwest U.S. during the early morning hours of the 17th. The surface low was over South Dakota as a line of thunderstorms developed ahead of an advancing dry line that was south of the low. The atmosphere was moderately unstable with about 2000 J/kg as the storms developed in the evening. CAPE in the -10 to -30 C layer of the atmosphere was only about 400 J/kg with a freezing level around 13,000 feet. The lifted index was in the -4 to -5 C range as the storms approached with 40 to 45 kts of shear available. The LCL was quite low, around 750 meters. CAPE in the zero to 3 km layer was 50 to 100 J/kg. Precipitable water values were quite high, in the 1.25 to 1.5 inch range. For the most part, the thunderstorms were not severe and produced mainly heavy rainfall. Several reports of 2 to 3 inches of rainfall were received from southwest into north central Iowa. As the line advanced eastward, a small mesoscale vorticity maximum was observed riding north along the line. The thunderstorms became enhanced as it moved north with a line of damage extending from Clarke County north to Webster County. Eighty two cars of a railroad train were derailed by the winds, with two of them blown off into the nearby field. Numerous very large trees were downed and some farm buildings lost roofs. Reports of trees and power lines being blown down continued north as the vorticity maximum lifted north.

A closed upper low lifted out to the west of Iowa with the surface low tracking northeast to near the Iowa-South Dakota border. A warm front extended southeast into Iowa and lifted north as the dry line pushed into western Iowa during the afternoon. The synoptic situation was fairly classic. The atmosphere was relatively unstable, though cloudiness limited that somewhat. CAPE values rose to 1500 to 2000 J/kg with a lifted index around -7 at the storms initiation. Downdraft CAPE was only 300 J/kg. There was 45 to 50 kts of effective shear however. CAPE in the -10 to -30 C layer was around 500 J/kg, with a freezing level around 12,000 feet. The parameters were favorable for potential tornado development with the LCL only 750 meters and 50 to 100 J/kg of CAPE in the zero to 3 km layer with steep lapse rates. Thunderstorms formed in an arc across western Iowa and quickly produced gusty winds and small hail. The cells tracked north as the line lifted northeast. Numerous reports of tornadoes were received. The reports were from the same tornado. Debris was reported with the tornado in Carroll County. Damage as done in the Lake City area of Calhoun County by a tornado, reported to be 1/4 mile wide by then. The tornado touched down northwest of Lidderdale and tracked northeast, striking the west side of Lake City. The tornado continued passing through rural Calhoun County and hit some power poles on the west side of Rockwell City before lifting about 2 miles north of Rockwell City in rural Calhoun County. Much of the damage included leaning power poles, tree damage and uprooted trees. In the town of Lake City, the roofing material was removed from the High School, and the roof was removed from a double-wide manufactured home and a warehouse building north of town. The tornado was of EF1 strength with winds of 100 MPH. The track was 23.5 miles long. Additional thunderstorms produced hail and high winds. An 80 MPH wind gust was reported west of Glidden, a machine shed was destroyed in Audubon County, and a weak shed was blown over in Cass County. Winds were measured at 65 MPH in Pocahontas. A strong storm moved through the Lake City area following the tornado and produced baseball size hail and destroyed a farm outbuilding west of Lidderdale.

Low pressure developed over southwest Kansas during the night of the 19th into the day of the 20th. The low turned northeast through Missouri into east central Iowa by the afternoon of the 20th. A strong surge of moisture pushed north ahead of the low with dewpoint temperatures in the 40s to low 50s to the south of the low pressure track. Northwest of the low, temperatures were quite mild for late February, generally in the low to mid 30s. The storm began as very wet snow. The wet snow continued into the evening hours and caused power outages. At one point during the night, Alliant energy had over 16,000 customers across northern IA and southern MN without power. Many of the small towns across the north and portions of Mason City were without power from the storm (either tree limbs down on power lines or power lines down). Also as many as 650 were out across central and southern Iowa. MidAmerican Energy reported over 600 out in Fort Dodge and over 300 out in Waterloo overnight. There were still 6000 out across the north with Alliant Energy and 14 out with MidAmerican in Waterloo as the sun rose on the 21st. Colder air began to move in during the evening hours. The sub-freezing temperatures changed the texture of the snow. Winds increased gradually during the afternoon and evening hours. Sustained winds were 25 to 35 MPH with gusts of 40 to 50 MPH through much of the night. Conditions deteriorated rapidly through the night. As the a band of snow moved across the area, near blizzard to occasional blizzard conditions were reported. Snowfall was generally in the 3 to 6 inch range across the area, however with the strong winds there was a significant societal affect with road conditions and business closings.

A narrow line of thunderstorms developed west of Iowa and advanced across the state during the evening of the 28th. Though there was no severe weather, some hail occurred with the storms. Lightning struck a transformer near Adel, causing a fire and knocking out power.

An area of low pressure formed over Oklahoma during the day on the 8th and advanced northeast across Missouri. There was strong support in the upper levels of the atmosphere as a negatively tilted shortwave lifted northeast out of the southwest US. A large deformation zone formed to the northwest of the low pressure. Snow began to fall over southwest Iowa by evening and spread into the central counties by mid to late evening. Snowfall amounts of 2 to 4 inches were common. Concentrated areas of heavier snow occurred in and along the center of the deformation zone, with a band of heavy snow extending from near the Lamoni area of south central Iowa, northeast to Winterset. In Winterset for example, 6.5 inches was reported by shortly before 0300 CST. Numerous power outages were reported in the area due to the heavy wet snow. The snow was heavy enough in Union County to topple high tension power lines. Temperatures were near freezing at the time the wet snow fell, causing it to cake on trees, which still had part of their leaves remaining. Power outages occurred in many areas, even with only 3 to 4 inches of snow due to tree damage. Damage was fairly extensive in portions of the metro Des Moines area, as was the case in most cities. At one point, nearly 10,000 customers were without power in portions of the Des Moines metro area, with over 500 still without power 24 hours later. Several hundred customers per county remained without power southwest through Madison, Union and Ringgold Counties as well.

A strong upper level trough lifted northeast from the southwest U.S. with the surface moving from central Nebraska at mid afternoon, and into eastern South Dakota by the early morning hours of the 24th. Very strong dynamics were in place as far as the low level jet near 65 kts being in place, and mid level flow in the 80 to 90 kt range. Instability was marginal with most unstable CAPE around 500 J/kg and available cape in the -10 to -30 C layer of the atmosphere in the 100 to 200 J/kg range. The shear was strong with 35 to 50 kts available. The LCL was relatively low at only 500 to 1000 meters. A strong surge of moisture pushed into the state in advance of the approaching low with precipitable water values over an inch. A line of thunderstorms developed in Nebraska and advanced east into Iowa. Strong surface winds developed ahead of the line. Although most of the storms were not all that strong, the antecedent winds were not that far below severe levels. A few of the storms were able to mix into the boundary layer and produce strong winds. A few gusts of 60 to 65 MPH were recorded. High winds turned a mobile home on its side and downed power lines in Adams County. Part of the roof was blown off of a home as well there. High winds also tore part of a roof off of a building in Adair County at Adair and took the canopy off of a gas station. As the storms moved through Dallas County, winds blew a barn off of its foundation in Dallas Center. Only one storm produced severe hail, though many produced pea size hail. Two small tornadoes touched down in Cass County southwest and north of Cumberland. The first was on the ground for several miles and caused damage in several places with grain bins destroyed, an anhydrous tank was flopped and leaking, trees and outbuildings were also toppled. The second was a brief touchdown and resulted in little damage south of Wiota.

The synoptic situation remained quite similar to that of the previous event. A second round of convection dropped southeast into Iowa. An MCS developed over northeast Nebraska and moved southeast into Iowa during the early morning hours. The lead edge of the system took on the form of a bow echo as it raced into the southwest and west central counties at nearly 50 MPH. High winds were reported with this bow echo, reaching speeds of 80 MPH west of the DMX CWA. Winds moved into west central and southwest Iowa in the 60 to 70 MPH range, downing trees and power lines. The bow echo lost strength as it advanced east into Iowa as the airmass was not as rich in the central counties. Gusty winds were reported, but most were in the 40 to 50 MPH range. One mesonet site in Boone County reported a 58 MPH wind gust with the passage of the outflow from the bow echo. Later, on the back side of the MCS, thunderstorm activity developed on the northeast outflow boundary. It was fed by a 50 kt low level jet and maintained itself through the night. These storms were marginal severe in nature and produced some spotty three quarter to one inch diameter hail reports received. One report of high winds was received from Guthrie County at Panora.