Minor lowland flooding begins along the Illinois River. Campgrounds become inundated, but structures remain mostly unaffected.
Low-lying areas near the river start to flood. Access roads to campgrounds may become impassable. Some campsites and picnic areas experience water coverage.
More widespread flooding of low-lying areas occurs. Several roads and campsites near the river become inundated. Access to riverfront properties may be limited.
Extensive inundation of structures and roads. Significant evacuations of people and/or transfer of property to higher elevations. Commercial river operations may be suspended.
Devastating flooding occurs along the Illinois River from near Hanging Rock to the headwaters of Lake Tenkiller. Homes, businesses, and infrastructure are severely impacted.