Catastrophic flooding unleashed by a powerful atmospheric river system has driven emergency relief efforts across western Washington, where the American Red Cross is providing shelter, meals, supplies and other essential support to thousands of affected residents.

Rivers that inundated towns and forced widespread evacuations are expected to remain at dangerous levels as additional rain falls over the coming days, prompting aid organisations and authorities to prepare for renewed flooding risks.

Red Cross disaster volunteers and partners have opened more than a dozen emergency shelters throughout the region, accommodating evacuees with safe places to rest, eat and access basic necessities.

Pets and service animals are also being welcomed at many sites, and additional shelters are being identified in coordination with state and local officials to meet evolving needs.

More than two thousand meals and snacks have already been served, and disaster response teams are working around the clock to distribute relief supplies and offer emotional support to displaced families.

Volunteers from multiple states, including California, Oregon, Idaho and Nevada, have deployed to Washington to bolster the response, bringing specialised skills and manpower for shelter operations and logistics.

A shelter in Burlington reached capacity with roughly one hundred and fifty evacuees, leading teams to open a second facility to manage the demand.

Red Cross personnel emphasise that their presence will continue as long as the need persists, from immediate relief to longer-term recovery assistance.

The scale of the flooding has been historic: tens of thousands of residents have been displaced, evacuation orders have been issued in numerous communities and emergency crews are actively engaged in mitigation and rescue operations.

The Red Cross response works in concert with local emergency management, the National Guard and other agencies mobilised under federal and state emergency declarations.

With forecasts indicating continued rainfall and rivers at or near record levels, officials and responders are preparing for further challenges as communities seek to weather the ongoing natural disaster.