LONGVIEW - A wall of water building in Spirit Lake at the base of Mount St. Helens remains unsteady and mysterious in its threat to 50,000 persons today.
No one knows for certain if or when it will go.
Officials say the wall is two-miles wide and the lake is now 200 feet higher than when Mount St. Helens erupted Sunday.
"Nobody knows what's going to happen because nobody's had experience with this kind of thing," said Dave Peterson, a spokesman for emergency services.
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Residents of areas along the Toutle and Cowlitz rivers not already evacuated went to bed Tuesday night being told they may not sleep through the night.
They did, but police cars with sirens and loud speakers were poised for designated areas of Kelso, Longview, Castle Rock, Lexington and outlying areas in case the natural dam at Spirit Lake gave way.
"We have no idea how many cubic feet of water has built up," said Sgt. Gary Greig, of the Cowlitz County sheriff's department.
It is known the lake is rising and expanding on a mountain some distance away and above the lake a map designer is charting its movement.
At night, aircraft using radar and altimeters check the surface to alert if a break occurs, said Peterson.
The lake water is now estimated to be 150 to 200 degrees Fahrenhite, he said.
Three sides of the once beautiful resort lake are now lined by ridges and described by witnesses as desolate.
There's only one way for the lake water to go if the dam breaks - down the north fork of the Toutle River to the main fork that leads to the Cowlitz River and Kelso and Longview.
Peterson said some water had seeped over the top and beneath the dam. The Cowlitz rose 2 inches by this morning, officials said.
If the dam should give way, and conflicting reports exist whether it will and to what extent, it is uncertain what the final impact will be for residents.
A wall of water cascading into heavily populated areas is unlikely, but flooding should occur at least in lower areas of Longview and Kelso, officials say.
The cities are 60 miles away as the rivers flow. Part of the flow might feed into Silver Lake ruining cabins there but reducing impact here, Peterson said.
Dikes protecting Kelso can take a crest of about 27 feet and those at Longview about 31 feet, Peterson said.
Monday's crest was 20 feet after the volcano erupted.
It's down to about 15 feet due largely to mud below the surface, one official said.
Water temperature is normally about 40-degrees this time of year, Peterson said. Monday the Cowlitz River had temperatures in the mid 80s, but it has since dropped.