By SETH TRUSCOTT

Snoqualmie Valley Record

While the potential for flooding looms over homes and businesses in the Green River Valley, residents of the Snoqualmie River basin have long lived with floods.

The communities of Snoqualmie, North Bend, Fall City and Carnation survived three significant floods in the last four years.

While many residents know to raise their belongings and leave or seek higher ground, many also choose to hunker down and ride it out.

“Every flood is a little bit different,” said Chris Connor, Fall City Fire Chief. A part of the district since 1981, Connor has seen a lot of floods, each one unique.

“A lot of time, it depends on how it rains and where it rains,” said Ron Garrow, Public Works Director for North Bend.

Weather patterns and snowmelt can make some river forks flow higher than others, or changes the timing and crest of a flood.

Still, some things are constant, such as the way the Snoqualmie fills and cuts off low-lying areas first, eventually rising to close highways and short-cut across fields, farms and golf courses.

When river waters rise, local emergency management agencies are notified and in turn warn residents in affected communities.

Fire departments, police and city officials use phone calls, emergency radio broadcasts, reverse-911 networks and door-to-door visits to urge floodplain residents to evacuate.

In Snoqualmie, warnings go out when the river reaches flood phase 2, which is calculated based on the sum of the Snoqualmie River forks gauges, at least 12,000 cubic feet per second.

“We have it down to a science on which communities are going to flood first, and which ones need to be notified,” said Snoqualmie Fire Chief Bob Rowe.

Flooding proceeds downriver from North Bend through Snoqualmie and Fall City to Carnation, almost like clockwork.

“It’s like a ball that goes through a snake,” said Lee Soptich of Carnation, chief at Eastside Fire and Rescue. “It starts off in North Bend. What happens in North Bend, we get about 12 hours later.”

Parts of downtown and much of historic Snoqualmie are affected by flooding. Flooding last January caused hundreds of thousands of dollars in damage to the Northwest Railway Museum’s train tracks in the Upper Snoqualmie Valley, and water was waist high in parts of downtown Snoqualmie. That flood was the fastest-moving event that Rowe has seen in his 10 years in the Snoqualmie Valley.

Like Snoqualmie, Fall City has a list of residences known to be impacted by floods.

“If it goes to 12,000 (cubic feet per second at the Sum of the Forks), we know we have some roads that are going to go under,” Connor said. During the January event, roads were wiped out and floodwaters tried to form a new channel across Twin Rivers Golf Course.

“When it starts blasting across there, that becomes the river channel,” Connor said.

Only a small percentage of the city of Carnation is waterlogged, but a bad flood will put water across Highway 203 on both sides of town, closing highway access. Some highland roads connect Carnation with the city of Duvall, but both cities can be isolated in bad floods.

“Last year was the biggest test,” Soptich said. Flooding damaged the Tolt River levy, but the breaches did not channel into the city.

January’s flood was strong enough to carve a path across Highway 202 just east of the Fall City bridge. A family was trapped in the ensuing deluge, and had to be flown to safety. Several family members and a dog were winched hundreds of feet into a hovering helicopter.

The successful Fall City helicopter rescue last January was a fluke. Half of the time, Connor said, such airlifts don’t work because pilots won’t risk their crews’ lives in unsafe flying conditions.

“We got lucky with that,” Connor said. “We had the right weather conditions, right pilot, right crew.”

That episode illustrates how dangerous it can be for families to stay behind when floods loom — and how lethal flood-covered roadways can be.

Most of the time, residents who stay behind are asking for trouble. While many people stay put during floods, Connor warns that their access can be cut off.

“They have to understand that if they have some kind of medical problem or fire, we’re not going to be able to help them,” he said. Even if access is available, it will take much longer for rescuers to reach flood-stranded residents.

The worst thing people can do in floods, though, is try to drive through them. Most people killed in floods die as a result of driving into flood waters.

“You don’t know how deep it is,” Connor said. “There’s the possibility that the road is washed out. If you drive into that, you’re probably going to lose your life.”

When the call to evacuate comes, emergency responders urge residents to seek shelter beyond the floodplain.

“Ideally, they should leave their homes,” Garrow said. “A lot of people don’t — they know how to cope, and stay on the second floor, or they think someone might vandalize (their home).”

Floodplain residents should expect flooding, and be prepared for it as early as November, when heavy rains begin, Garrow said.

“It would be nice if we could keep the water in the river, but that’s not going to be the case,” he said.

Valley residents generally handle flooding very well. For many residents, “it’s almost a yawner,” said Soptich. “People are used to it, because it occurs so often.”

Snoqualmie flood stages

Snoqualmie River flood phases, based on the Sum of the Forks gages:

Phase 1: 6,000 cubic feet per second

Phase 2: 12,000 cubic feet per second

Phase 3: 20,000 cubic feet per second

Phase 4: 38,000 cubic feet per second