Rivers flood in Iowa. It’s a regular occurrence for people who live along the rivers. But, flash flooding can unexpectedly strike, causing flooding on streets, sending small creeks and streams out of their banks and quickly creating dangerous conditions for Iowans.
Flash flooding can develop in hours or even within a few minutes, leaving a small window for emergency notification and response.
Texas experienced this when devastating flooding swept through the state over the Fourth of July weekend. The catastrophic flooding killed at least 119 people and left another 170-plus missing as of June 10. Even though the National Weather Service issued 22 warnings, many residents said they didn’t receive the alerts or understand the severity, according to CBS News.
Iowa has had its own cases of disastrous flooding, too. The Des Moines metro area saw “epic” flash flooding due to heavy rain in June of 2018. The thunderstorms dumped 5 to 10 inches of rain over northern Polk County, according to the National Weather Service.
More recently, northwestern Iowa experienced record-high river levels that resulted in at least one death. The flooding in 2024 damaged hundreds of homes in the process.
How will the National Weather Service and local emergency managers alert Iowans to flood risks?
What are the different flood alerts?
There are four different classifications of flood alerts, according to the National Weather Service.
The alerts can either be for flash floods or flooding. There are also warnings, watches and advisory notifications, all with different meanings:
Flash flood warning: A warning means you need to take action. When these warnings are issued, flash flooding is imminent or ongoing. If you are in a flood-prone location during this warning, the National Weather Service advises moving to high ground immediately. Flash floods are sudden and violent.
Flood warnings also mean to take action because flooding is likely or occurring, according to the National Weather Service. These are issued when hazardous weather events are imminent or ongoing.
Flood advisories warn of potential flooding, not bad enough to issue a warning, but the flooding may cause inconveniences. These are issued when forecasted weather events become a nuisance.
Flood watches are issued to prepare people when conditions are favorable for specific hazardous weather events, according to the National Weather Service. This doesn’t mean flooding will occur, but it could.
What kind of emergency flood notifications does Polk County send out?
AlertIowa is a statewide notification system managed by counties that provides local information to residents regarding weather alerts. When Polk County residents sign up, they decide how the warnings will be issued to them, whether that be by text message, automated phone call, email or a combination.
AlertIowa sends out notices for all flash flood warnings depending on the user’s address. To sign up for AlertIowa, visit the Iowa Homeland Security and Emergency Management.
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Depending on your phone and notification settings, these text messages or phone calls may not wake you up in the case of a hazard while you’re sleeping.
The Polk County Emergency Management encourages Iowans to have multiple ways of getting emergency weather notifications, program assistant Brett McIntyre told the Register. NOAA Weather Radio broadcasts continuous weather information from the nearest National Weather Service office. These devices are designed to wake you up in an emergency.
Are outdoor sirens triggered during emergency flooding in Polk County?
Sirens are not triggered during flooding or flash flooding in Polk County. Outdoor warning sirens are only activated for tornado warnings or severe thunderstorm warnings with wind speeds of 70 mph or greater.
Sirens are also designed to alert people outdoors and may not be audible indoors or loud enough to wake you up overnight.
Will my cell phone alert me to flooding in Iowa?
The National Weather Service does issue wireless emergency alerts sent to all cellphones in the warned area, McIntyre said. These are the types of alerts that make an alarm blare on your phone, regardless of your notification settings.
However, these notifications are only sent when the flash flood warning is tagged as “considerable” or “catastrophic.” If your phone is turned off or you have the emergency alerts setting off on your phone, then you will not receive the notification.
What should you do during a flood?
Polk County officials encourage all Iowans to stay up to date on forecast conditions, knowing if you live in a flood-prone area or if you are going to visit one, McIntyre said.
“That is the first step is being aware if flooding is a risk that I could run into today or tomorrow,” McIntyre said.
Also, have a plan if you are in an area with a flood risk. Create an evacuation plan, so if flooding happens, you can remove yourself from harm’s way. Also refrain from entering floodwater. It can carry diseases or debris that can result in injuries.
“With water, it’s easy to let your guard down around it because it is fun to be around and interact with, but it does have quite a bit of danger if you are not careful,” McIntyre said.
For more information on what to do before, during and after a flood, visit Ready Iowa’s website for tips on how to be prepared for emergencies and disasters.
Kate Kealey is a general assignment reporter for the Register. Reach her at kkealey@registermedia.com or follow her on Twitter at @Kkealey17.
This article originally appeared on Des Moines Register: Iowa flood alerts: How to receive NWS, AlertIowa notifications