Partial County Alerting- What it is and How It Could Help
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Weather and emergency alert radios bring households across the country life-saving information during severe weather and emergencies.
Learn more about Partial County Alerting and when implemented, how it could impact counties everywhere.
What is Partial County Alerting?
Public Alert-certified emergency radios are manufactured to safety and performance standards that require, among other things, Specific Area Message Encoding (S.A.M.E.).
S.A.M.E allows you to program the radio to alert for only your county, greatly reducing bothersome warnings for storms and emergencies far away. However, in some of America’s largest counties, an emergency alert radio programmed for only that county could alert you for a severe thunderstorm that will never affect you. These radios should save lives, not bother them.
Partial County Alerting in action
Comprising more than 8,000 square miles, Clark County, Nevada is larger than the entire state of New Jersey. It encompasses Las Vegas, a few dozen small communities, and miles and miles of desert and mountains, which are prone to flash floods and dust storms. It's unlikely the 2 million people living in Las Vegas want to be woken up when it's flooding 80 miles away in Mesquite.
That’s why Clark County was the perfect testbed for Partial County Alerting (PCA). Adjusting the first digit of the county’s standard S.A.M.E. code, National Weather Service-Las Vegas partitioned Clark County into 6 sectors, based upon population areas and watersheds. Those landscapes are most prone to flooding.
Splitting the county up into 6 zones, they created new S.A.M.E. codes, allowing more finely tuned alerts.
Because the 2-year test was such a success, PCA will be integrated into all 122 National Weather Service forecast offices in 2026.
How Partial County Alerting works
Every county in America has a unique 6-digit S.A.M.E. code, starting with 0.
When you program your emergency alert radio, by either manually entering that digital code or by choosing “USA-Nevada-Clark County” in radio set up, the county code tells the radio to alert for only that county. The first digit “0” means “alert for this entire county."
Counties can split their land into up to 9 zones. Partial County Alerting overlays a 9-digit grid on the county, and new partial county S.A.M.E. codes are created.
The “all county” 0 can now be replaced with a “my section of the county” digit ranging from 1-9.
Once the first digit of your county’s S.A.M.E. code has been adjusted, your radio will alert only for the specified county section. You’ll receive fewer warnings and the ones you get will be more pertinent.
Will my county use Partial County Alerting?
Most counties will not.
PCA was designed for those few counties that are oddly shaped, large, or otherwise troublesome. For example, Chicago’s Cook County is a very long county with a population of more than five million people. Why alert everyone in Arlington Heights for a tornado in Orland Park, 30 miles away? In Cook County, programming a different first digit can save millions of people from unnecessary disruptions, but because the vast majority of US counties don’t have issues like Clark and Cook, most will keep a “zero” as their first SAME digit, requiring no adjustment to your radio.
How do I know if my county uses PCA?
This information will be shared on the National Weather Service’s official website.
Click on the name of your state, then click on the name of your county. If your county has opted into Partial County Alerting, you’ll see something like this, showing first digit adjustments you can make. If you prefer to hear alerts for your entire county, leave the first digit a zero, as is standard.
Sonoma County, California is setting a standard for PCA, partitioning the county based upon its official wildfire evacuation zones. Midland WR120 emergency alert radios in the county can be easily reprogrammed to adjust the first digit of the Sonoma County SAME code, ensuring more finely-focused warnings. If the first digit remains a “zero”, the radio will alert for all sectors of the county.
It’s important to remember to adjust for PCA only if your county has opted into it. If PCA is not active in your county, there is nothing you need to, or should, do. Leave your county SAME code “as is” and your Public Alert-certified radio will continue to protect you and your family when weather or wildfire threatens the area.
Questions about Partial County Alerting
Contact Midland's customer experience team- support@midlandusa.com and we'll be happy to assist you.
