(Tacoma, WA)  --  Pierce County is working to upgrade a warning system intended to alert residents about volcanic mudflows, also called lahars, that would result from a Mount Rainier eruption.  County officials say the displacement projection for a Mount Rainier lahar is between 250- and 500-million cubic meters of mass, compared to the roughly eight-million cubic meters that were moved by the Oso landslide.  Pierce County's emergency-management department tells the "Seattle Times" Mount Rainier rumbles with volcanic mudflows every 500 to one-thousand years and that the state is "in the window."  Emergency Management deputy director Scott Heinze says the department will ask the Legislature this year for additional money to install about double the current number of warning sirens that are set up from Orting to the Port of Tacoma.