A Wednesday evening snowfall surprised motorists and created traffic gridlock on untreated roads across the Washington region.

Frustrated D.C. drivers took to social media to document their commuting woes on Jan. 20. Light snow fell and caused traffic jams and minor crashes on busy, slick roads. (Jenny Starrs,Victoria Walker/The Washington Post)

While the city prepares for the arrival of a potentially historic storm on Friday, motorists were caught off-guard during a storm system that dropped about an inch of snow Wednesday. Many roads were untreated, creating lengthy, slow-moving commutes.

Here’s a look at the road conditions across the D.C. area on Wednesday. Roads were expected to be covered in many more inches of snow to end the week.