The first big snowstorm of the year hit, and the missing wiper arm slowed driving to a crawl.
From the denverpost.com
A wiper generally consists of an arm, pivoting at one end and with a long rubber blade attached to the other.
From the en.wikipedia.org
Joyce's girlfriend told police she got into an argument with Joyce, he hit and broke the rearview mirror and windshield wiper control in her car, and struck her right arm in the process.