Deadly Dust A case study of a Great

Deadly Dust: A case study of a Great Plain dust storm J. Tatarko, USDA-ARS; M. Knapp, Kansas State University; S. van Donk, and E. L. Skidmore, USDA-ARS; Manhattan, Kansas Introduction 15: 30 MDT – Goodland, Kansas ~15: 45 MDT – Bird City, Kansas WEPS Simulations On 29 May, 2004, a system of severe thunderstorms in The National Weather Service (NWS) in Goodland, Kansas reported “My anemometer is located only 9 feet off the ground and between Weather and field data provide a unique opportunity to assess the ability of the northeast Colorado produced an outflow boundary of cold air. 90 mph winds at St. Francis, Kansas and gusts 65– 85 mph at windbreaks and registered in the 50 -60 mph range but neighbors WEPS model to simulate such wind erosion events. For the period 1999 -2004, we This outflow and resulting temperature gradient contributed to Goodland. Prior to this event, the area experienced a six year clocked 80 -90 mph straight lined winds. It was an unbelievable obtained detailed historical weather records, soil data for the dominant soils, winds with gusts as high as 40 m/s (90 mi/h). The storm drought (see table below) and the topsoil moisture in NW Kansas storm. It reminded me of some hurricane videos I've seen. The average yields, and typical crop rotations for Goodland, Kansas. These data tracked towards the east-southeast, over land that had been was very low by the end of May. Afternoon temperatures roar grew until our house shook. The south side of the barn was were used in WEPS and simulations made for 6 year rotations and the event experiencing an extended drought. The wind, in conjunction frequently topped 80 degrees during the month, and only two days blown off its foundation. ” - John Coumerih, Bird City, Kansas (5/29/04) using measured and simulated weather (see table below). with the land condition, initiated a wind erosion event that of significant rainfall were reported for the year, prior to May 29 th. Storm observations indicate that while the soil eroded on many fields, on others carried soil dust for at least 355 km (220 miles) past Hays, 16: 00 MDT – Colby, Kansas. The dust storm caused severe damage to the land dramatically lowered visibility. Many traffic accidents and even it did not (see aerial photos). Interviews with the Goodland DC indicate that crop rotations on fields that eroded included grain sorghum, corn, and some winter Robert Grace took a series of photos flying near Colby, Kansas. NWS reports winds of wheat where the previous drought afforded little residue and poor crop stands in 67 mph and “metal roofs ripped from buildings and several power poles were broken”. two deaths were attributed to the storm. This study helps to the spring of 2004. While WEPS did show soil loss likely for the rotations using better understand the genesis and progression of such storms simulated weather, losses were much greater using the much drier measured and to evaluate the ability of the USDA-ARS Wind Erosion weather on irrigated crops and still higher for dryland situations. Corners of Prediction System (WEPS) model to simulate such events. some irrigated fields blew (see aerial photos, left) and are considered as dryland 11: 45 MDT – SE of Akron, Colorado Sherman Co. (Goodland) precipitation and departure from normal A severe thunderstorm system, southeast of Akron, Colorado, Year: 2000 2001 2002 2003 2004 Normal causes a downburst. A downburst is the result of hail or large millimeters: 427 466 280 373 566 504 raindrops falling through dry air. The hailstones melt or scenarios in the simulations. The Goodland DC indicated that some wheat land departure: -77 -38 -224 -131 62 was blowing on 29 May, but WEPS does not show loss for that day for wheat. However, others interviewed indicated that most wheat land did not erode on 29 May because of sufficient cover but that such land did have erosion events in April because of poor cover. WEPS did predict erosion on 16&17 April of 2. 6 and raindrops evaporate – the evaporation demands a lot of energy 7. 7 kg/m 2 respectively. Dryland grain sorghum and corn did show significant soil so the air is cooled. The higher density cold air falls as a "cold loss for 29 May as was observed in the field by the DC. air balloon". As the cold air balloon falls, a strong downdraft induces an outburst of damaging winds on or near the ground. 17: 15 MDT – Grinnell, Kansas The poor visibility caused the Kansas Highway Patrol to close I-70 West of Wakeeney for about two hours. However, because of the fast moving nature of the storm, at least 10 vehicle accidents occurred with two resulting in the deaths of two individuals including Kansas State Senator Stan Clark. NWS reports winds of 69 MPH. The study of this storm will help in our understanding of such events including management systems that control soil loss by wind under these conditions. This study also provides experience using WEPS with measured weather - essential to developing a WEPS based dust event warning system for highway, agricultural, and environmental agencies. For more information about WEPS, please contact : USDA-ARS-WERU 1515 College Ave. Manhattan, KS 66502 Email: weps@weru. ksu. edu; Phone: 758 -537 -5559