Case
Study 040"Kansas
City/Brush Creek Flash Flood"
04 October 1998
Case Summary
The Kansas City flood hit the afternoon and evening of October 4, 1998. Parts of the metropolitan area received almost eight inches of rain that day with some locations hit by a five-inch in one hour deluge. The downpours resulted in considerable flash flooding, 12 deaths, and millions of dollars in damage.
The heavy precipitation that fell that day was associated with a system consisting of an upper-level trough, which entered the U.S. in the Northwest, and a slow-moving surface system. The negatively-tilted trough dug into the central U.S. and cut-off by 2100Z 4 October. The cutoff low moved very little over the next 18 hours. The associated surface low, here at 1200Z in southeast Colorado, mimicked the path of the upper system, moving slightly east of north, to north central Nebraska by 0000Z 5 October.
The flood-bearing storms began to fire early on 4 October, in the vicinity of a surface boundary in southwest Missouri. The storms moved to the north-northeast along with the surface system, and hit the Kansas City area with it's first round of heavy precipitation around 1800Z. A new line of convection formed along and ahead of the surface cold front around 2100Z, and developed explosively in the next three hours, with a new surface low forming in east central Oklahoma.
The line of precipitation moved west to east, while the individual cells in the line moved from southwest to northeast. This motion, combined with the slow movement of the line, caused areas of heavier precipitation in lines similiar to the movement of the cells, as can be seen in this precipitation totals graphic from Kansas City.
The NWS Forecast Office in Pleasant Hill (Kansas City) was praised for their forecasting and warning of the events. An excerpt from the November 1998 NWS Central Region Highlights:
| "The forecast staff at Pleasant Hill issued numerous flash flood warnings that clearly stated the dangers and advised against travel, with the first warning having at least 30 minutes lead time. Despite the excellent effort, more than 100 water rescue efforts were reported. Most of the deaths were people who drove their vehicles into rushing waters -- in many cases, despite being warned by witnesses not to do so. Seven people died after their vehicles were stranded on a single bridge over Brush Creek. Rivers rose rapidly overnight. Most all river flood warnings were issued well in advance of the rivers reaching flood stage with lead times of 6-18 hours for the faster rising streams, and 3-4 days for the lower Missouri River." |