An intense hailstorm that came through northern Clackamas County just as rush-hour traffic was picking up about 5 p.m. Monday slickened roads and caused minor flooding.

Parts of McLoughlin Boulevard north were briefly limited to one lane in the Milwaukie area, and power lines were down at 23rd Avenue and Southeast Lake Road. The hail, accompanied by thunder and lightning, came down so quickly that streets and yard turned white.

Residents of Milwaukie tweeted that the hail was up to a half-inch in diameter.

The Lake Road power outage knocked out stoplights, backing up traffic throughout Milwaukie.

Another power outage was reported in Oregon City, affecting 1641 customers.