OLYMPIA — The state panel responsible for regulating logging was expected Tuesday to consider a halt to timber harvests in certain landslide-prone areas, a move environmentalists and a Snohomish County leader say is needed to ensure public safety.

Snohomish County Council Chairman Dave Somers wants the Forest Practices Board, of which he is a member, to prohibit logging on land with geology similar to that of the hillside in Oso which gave way March 22, killing at least 41 nearby residents.

Somers said he’ll propose the ban at a meeting Tuesday, although he admitted the panel might not feel empowered to take such action. The Forest Practices Board gathered this week to examine state rules for logging near unstable slopes.

“I think we have the full authority to take action for public safety reasons if we deem it to be an emergency,” he said Monday after the board session. “In my opinion, we ought to be absolutely the most cautious where public safety is concerned.”

Somers wants to halt logging in groundwater-recharge zones of glacial deposits that may be prone to deep-seated landslides. This is the geology of Hazel Hill, where a state-approved clearcut occurred in 2005. That cut is under study as a possible contributing factor in the deadly mudslide that wiped out the Steelhead Drive neighborhood along the North Fork Stillaguamish River. Some landslide experts are already on record saying the clearcut had no effect, others say more study is necessary.

Somers said he envisions a prohibition until more is known about the effects of logging in such areas. It would give the Forest Practices Board time to consider permanent rules.

What Somers will propose is pretty much what a coalition of environmental groups urged during Monday’s Forest Practices Board meeting.

Peter Goldman, director of the Washington Forest Law Center, said the state needs to map slide-vulnerable areas, then have scientists figure out if logging increases the risk of catastrophic events. Until that determination, Goldman said, timber harvests should be banned in those areas.

Goldman said clearcutting in groundwater-recharge areas can lead to soggy soils, more sediment runoff and an increased potential for landslides.

“Oso was a wake-up call,” Goldman said.

Mark Doumit, executive director of the Washington Forest Protection Association, said a ban on permits is unnecessary.

“We are already not logging in those areas,” said the leader of the trade association of private forest owners. “We don’t think it’s needed.”

Talk of a moratorium culminated hours of sometimes mind-numbing reports to the Forest Practices Board about how the state detects landslide hazards, how existing rules for harvesting timber in areas with steep slopes are carried out and what steps are taken to protect people and natural resources from landslides.

The board is an independent state agency that develops rules for logging on public and private lands. It includes representatives of the state departments of Ecology, Agriculture, Fish and Wildlife, a timber products union and a small forest landowner.

Somers is the representative of county governments, and Aaron Everett, state forester with the Department of Natural Resources, is chairman.

The special meeting included a report on the Oso mudslide by a U.S. Geological Survey scientist, who said a cause may never be clearly known. Jonathan Godt said rainfall likely contributed to the “initiation of the landslide.”

But what caused it is “a question that may not be answerable in a satisfactory way” because much of the evidence is gone, Godt said.

“You can’t put the slide back up on the hill,” he said.

A recurring theme Monday was that not enough is known about landslides and logging, despite all the scientific data compiled by the Department of Natural Resources.

Members heard repeatedly of the added value of LIDAR, a remote sensing technology used to map topography.

“LIDAR is the best tool we can use to know what is going on in the landscape,” said Donelle Mahan, assistant division manager of operations for DNR, in a presentation on the permitting process. “It is like it almost takes the gauze away from your eyes.”

LIDAR is not cheap. The state has done some LIDAR mapping and it would cost about $20 million to fill in gaps statewide, or $4 million to $5 million for Western Washington alone, said state geologist Dave Norman.

At the end of the day, board members expressed interest in encouraging state lawmakers to help cover that cost for the Department of Natural Resources.

Several said they also want the board to look at rules to make certain the safety of people is a higher priority in the logging permit process.

“Public safety is something we have to pay attention to that we haven’t paid attention to,” said member David Herrera, an appointee representing the general public.

During public testimony, Deborah Durnell, whose husband, Tom, was killed in the slide, asked the board to do all it could to prevent future landslides.

“The deaths in Oso weren’t just statistics to me,” she said. “We owe every person who died to do all in our power to make sure that logging regulations are adequate and that they are enforced.”

She said she hopes the disaster motivates the state to ramp up efforts to identify risks, pass regulations, and notify residents of the hazards to ensure the public is protected.

The Associated Press contributed. Jerry Cornfield: 360-352-8623; jcornfield@heraldnet.com.