7500 CFS isn't considered high for the Cowlitz. The average flow for Nov. 22nd over the past 64 years is 8500 CFS. The Cowlitz is generally fishable up to 12,000 - 13,000 CFS. This USGS site gives you current river flows with averages.

http://wa.water.usgs.gov/rt-cgi/gen_stn_pg?station=14238000