SNOHOMISH — The flooding Friday wasn’t the deluge initially projected.

But it was only round one.

“We’re looking at sort of a one-two punch,” said Scott North, a spokesperson for Snohomish County’s Department of Emergency Management.

This weekend will see more rain and, by Monday, potentially more flooding.

Friday’s bout of rain was the result of what meteorologists call an atmospheric river: a long tendril of water vapor that hit the region from far away, like a rainy whip.

The Stillaguamish River rose above 14 feet around 9:30 a.m Friday in Arlington. By 11 a.m., the Skykomish near Gold Bar went over 15 feet. Major flooding for those rivers is anything over 19 feet.

Of the county’s rivers, the Snohomish went the highest: over 23 feet by 3 p.m. Friday. It was forecast to reach moderate flooding and peak at over 27 feet early Saturday morning, according to the National Weather Service. That has the potential to flood the Snohomish-Monroe Highway.

Sultan Mayor Russell Wiita didn’t seem too concerned, even as flooded roads cut off a few hundred people who live at Devil’s Elbow, along Mann Road.

“They’re used to the flooding and have to make arrangements,” he said.

Floods like these happen a handful of times every season there, Wiita said. The city has 18 pallets of sandbags at the ready, but as of Friday afternoon, no one had asked for any.

As a precaution, Sound Transit cancelled on Friday the north line of the Sounder commuter train that runs from Everett to Seattle through landslide-prone Mukilteo. And a school bus line in Sultan flanking the Skykomish River was called off in anticipation of surging water.

No major road closures had been made as of Friday afternoon.

By then, the heavy rain had tapered off, giving a much-needed respite to the county’s rising rivers.

Moments without rain are an opportunity to go out and clear leaves from neighborhood storm drains, said Justin Pullin, a meteorologist with the National Weather Service.

Pullin expected another wet and windy system to come through Saturday night and continue into Monday. That could cause continued flooding for the Skykomish, Snohomish and Stillaguamish rivers.

The second system will also drop more rain onto the already-saturated ground, heightening the risk of landslides and falling trees.

At least one tree fell Friday morning, knocking out power to 150 homes in Edmonds.

The U.S. Army Corps of Engineers was dispatched to several Western Washington rivers, including the Snohomish, where officials were checking on vulnerable levies Friday.

For the next few days, North said, motorists should avoid driving through water on roadways, “because you really can’t tell how deep it is or how fast it’s running.” Even a foot of water can float a car.

People should be aware near creeks, as well. Small waterways can contribute to urban and lowland flooding.

“Streams in Western Washington probably qualify as rivers everywhere else in the world,” North said.

Flood conditions can put people in peril quickly.

On Dike Road west of Arlington, two people camping by the Stillaguamish River had to be rescued Friday afternoon when the river quickly rose around them, said Snohomish County Fire District 21 Chief Chad Schmidt. The Stillaguamish Water Rescue Team used an inflatable raft to get the pair safely back to dry land.

It’s best to exercise caution, and to stay informed. Two 24-hour flood information hotlines provide updates about specific rivers.

• For information about the Skykomish, Snoqualmie and Snohomish Rivers, call 425-388-3653.

• For information about the Stillaguamish River, call 425-388-3702.

• For the latest conditions, visit Snohomish County flood watch website. It updates every five minutes.

The following safety tips come from the Snohomish County flood safety guide:

• If you have time before evacuating, turn off all utilities with the main power switch.

• Do not touch electrical equipment unless it is in a dry area.

• Do not try to walk, wade or drive through flooded areas.

• If you cannot safely leave your house, bring your family, pets and supplies to the second floor or the roof of your house and call 911 for help.

Herald writer Zachariah Bryan contributed to this story.

Jake Goldstein-Street: 425-339-3439; jake.goldstein-street@heraldnet.com. Twitter: @GoldsteinStreet.

Claudia Yaw: 425-339-3449; claudia.yaw@heraldnet.com. Twitter: @yawclaudia.