The impending rain is a big concern in the North Bay fire zones, emotionally and environmentally.
In Sonoma County, the race is on to protect rivers and streams from dangerous toxic debris runoff. Some fire victims in the burn zones are trying to get cleanup work done before the rain comes while water quality experts are working to protect waterways from dangerous runoff.
Many of the victims are still hoping to find personal mementos in the ashes, a search that may have to end as rain moves in.
"Feeling like the rain is gonna really change all that, change what's there and what's possible to be found," one fire victim said.
Water quality experts are concerned about rain washing toxic ash and debris into more than 600 streams in the burn zone. They say the natural watersheds typically filter out the water supply, but it's especially important to prevent ash and pollutants from getting into streams.
"We’re really concerned about protecting the streams because they're drinking water supply for most of Sonoma County residents," said Claudia Villacortawiththe North Coast Regional Water Board. "Our natural water sheds filter this drinking water supply system. It’s really important to prevent all this ash and pollutants from getting into the streams."
Crews also were installing filters on storm drains, placing nearly 200 straw wattles in burn zones. The straw wattles filter out toxins that otherwise could pollute drinking water supplies and harm aquatic life.
The Environmental Protection Agency continued working to clear hazardous materials from burn sites. The agency said it is halfway through that process.
During the weekend storm, people are asked to drive cautiously and use sandbags.
NBC Bay Area's Pete Suratos contributed to this report.