Please Note: This story has been updated on Jan. 15 HERE

Rescuers entered the mud flow area Thursday at about 9:30 a.m. in Dodson, west of Cascade Locks, where a woman is believed trapped in her car under the mud mud flow. According to an OregonLive report, Jennifer Moore of nearby Warrendale evidently went missing Jan. 13. Authorities believe the SUV she was driving is somewhere under up to 10 feet of mud.

Chris Liedle of Multnomah Sheriff’s Office, which is coordinating the search near Ainsworth State Park, called it “a very slow and methodical search.” Planning and mobilization started Jan. 13 as authorities determined the stability of the upland area, in the interest of safety of the searchers.

Interstate 84 eastbound from Troutdale to Cascade Locks was closed Wednesday but one eastbound lane is now open, according to Liedle.

He said Portland Fire, Lake Oswego Fire, Oregon State Police and Clackamas and Multnomah County teams are involved in the search, and Oregon Department of Transportation crews are working on the ends of the flow to begin removing debris to clear Northeast Frontage Road, which runs along the freeway.

“We are seeing a lot of what you would see for marine rescue events, including foam boards, rope and inflatable crafts,” Liedle explained. The foam boards are used to help searchers navigate and even stand up atop the mud flow, and are more puncture resistant than the inflatables.

“The mud poses tremendous challenges, and it is unlike other searches on water or solid land because mud is thick but it has water in it and it is very difficult to know if a searcher is going to step on firm ground or soft,” Liedle said, “and inside the mud there are other hidden objects like boulder, logs, and debris, and anything in the area where the debris flow came to rest.”

Liedle said no structures are known to have been involved in the debris flow.