The Northwest contingent of the American Red Cross already has boots on the ground in flood-ravaged parts of Texas following Hurricane Harvey, and more help is on the way.

Twelve members of the Northwest Region of the Red Cross went to Texas ahead of the storm. More personnel were slated to leave Sunday.

How you can help Northwest Response: Texas Floods

Most of their work is helping people in shelters.

"That's where the greatest need is right now. Thousands of people have evacuated their homes," said Colin Downey, Red Cross Northwest Region Communications Director.

More than 1,800 people piled into 34 Red Cross and community shelters in Texas Saturday night, according to Downey. Those numbers are expected to grow in the coming days as flood warnings and potential flash floods persist.

"This is going to be going on not for days or weeks, but months," said Downey, referring to the need for shelters going forward.

Hundreds of people have reportedly been rescued, and tens of thousands will be without power for awhile.

The Red Cross says numerous hospitals, nursing facilities, and dialysis centers are closed.

The Red Cross says it has enough shelter supplies in Texas to support 28,000 people and supplies for an additional 22,000 people are being sent in now. The agency is also sending in ready-to-eat meals and has blood supplies on standby.