After a week of unseasonably warm weather, temperatures began to rapidly plummet Monday as snow squalls blew across Iowa, briefly creating near whiteout conditions that led to several wrecks including a massive pileup on Interstate 80 near Altoona. The Iowa State Patrol said one person was seriously injured in a crash involving about 50 vehicles Monday afternoon in the westbound lanes of I-80 near the Highway 65 interchange, blocking highway traffic in the Des Moines metro area.