EVERETT — The legal battle over whether Snohomish County’s land-use decisions contributed to deaths and property loss during the Oso mudslide has just begun, but it’s already getting expensive.

The County Council on Monday approved spending up to $500,000 for an outside law firm to help defend against lawsuits stemming from the March 22 slide. The disaster left 43 people dead, buried about 40 homes and wiped out a stretch of Highway 530.

“Having outside assistance would be a great benefit,” said Jason Cummings, the county’s chief civil deputy prosecutor.

Lawsuits are likely to hash out whether the county or state agencies neglected any duty to alert people in the Steelhead Haven neighborhood that the hillside above them posed a danger.

A joint state and county expert commission has deliberately steered clear from questions of fault. That group is finalizing its report on planning and public safety recommendations to keep people out of harm’s way during future landslides. They’re scheduled to meet again Tuesday before sending more than 20 recommendations to Gov. Jay Inslee and County Executive John Lovick.

The county’s contract with Seattle law firm Calfo, Harrigan, Leyh &Eakes LLP would last for up to three years. It was drafted in response to the first slide-related lawsuit filed against the county in July, but could apply to others. That includes a second lawsuit filed against the county in October.

The contract does not include the cost of other experts the county expects to hire to prepare its defense, Cummings said.

The initial lawsuit was filed against the county and state Department of Natural Resources on behalf of Lewis and JuDee Vandenburg, 71 and 64; Shane and Katie Ruthven, 43 and 34; and the Ruthven children, Hunter and Wyatt, 6 and 4. The Vandenburgs were Shane Ruthen’s mother and stepfather. They lived next door.

Seattle attorneys Guy Michelson and Emily Harris filed that case.

The second lawsuit alleges that officials working for Snohomish County, the state of Washington and a Skagit County-based logging company all played roles in setting the stage for the Oso tragedy. It was filed on behalf of 10 different families by Seattle attorneys Corrie Yackulic and John Phillips.

Additional damage claims are pending.

Noah Haglund: 425-339-3465; nhaglund@heraldnet.com. Twitter: @NWhaglund.