The specially trained team is one of eight search-and-rescue task forces in California that can be activated by the Federal Emergency Management Agency for disasters.
The city of Riverside will be reimbursed by FEMA for the costs of bringing in substitutes while the firefighters are in Washington.
Search-and-rescue equipment, satellite phones, ATVs, tents, fuel tenders, two tractor-trailers with generators and office equipment will also be sent, Riverside fire officials said.
In Washington, search and cadaver dogs are leading the way with hundreds of rescuers and heavy equipment operators following through the muck and rain.
Two bodies were recovered Tuesday, and another eight were located in the debris field from Saturday's slide 55 miles northeast of Seattle.
That brings the likely death toll to 24, though authorities are keeping the official toll at 16 until the eight other bodies are recovered.
With scores still missing, authorities are working off a list of 176 people unaccounted for, though some names were believed to be duplicates. That number was revised down to 90 on Wednesday.
Authorities said that number will change because more people have called in since the nearby logging town of Darrington's power was restored Tuesday.
The Associated Press contributed to this report.