Emergency managers and flood control officials are on high alert after the first El Niño-related storm hits the Valley.
Meteorologists with Maricopa County Flood Control said they are actively monitoring water level checkpoints across the Valley.
"It's an issue of how much rain and how fast," Maricopa County Flood Control spokesman Daniel Henz said.
"Soil is a big factor. We've been really dry for two months now so it's going to take a little bit of rain to wet the soils before we start seeing runoff. That's what's going to come into play later in the week," Henz said.
Officials said that, while levels look good right now, there are five specific areas of concern: Skunk Creek near Cave Creek, Indian Bend Wash in Scottsdale, the area immediately north of South Mountain, Washes near the White Tanks Mountains, and Washes along Highway 93 near Wickenburg.
The threat of El Niño storms has had emergency management officials preparing for months.
Wendy Smith-Reeve, of the Arizona Department of Emergency and Military Affairs, said her office has been meeting with other emergency management offices across the state to discuss preparation and resources.
"All of our staff is well aware of what the situation could be, and so all our staff is ready to respond at a moment’s notice," Smith-Reeve said.
Federal officials are also preparing for El Niño storms. F. E. M. A said they are in the process of hiring as many as 500 new disaster reservists, who will be on-call as needed. They are charged with responding to disasters and helping to organize recovery efforts.