08/12/2026
We recently received a great question from a follower regarding how our outdoor warning sirens operate, specifically during the severe weather events on Monday, July 27th. That day was unique because our team was already in the middle of conducting previously scheduled maintenance testing when the storm system developed.
We want to share a look behind the scenes at what was happening with the weather that morning, how our systems responded, and how you can best prepare for future storms.
Our Testing That Morning
On July 27th, we began our planned annual maintenance testing at 8:00 AM. During this type of technical maintenance, sirens are not activated all at once; instead, each unit is individually activated one by one by a technician physically working on that specific piece of equipment. Our last technician test activation occurred around 10:30 AM. At that point, given the rapidly changing weather forecast, we stopped all testing to ensure the full system was completely clear and ready for a real emergency activation if needed.
How the Timeline Unfolded
There is often confusion regarding how different emergency notifications reach the public. Here is how the story of that afternoon unfolded as the layers of defense rolled out (all times are approximate):
• 12:10 PM: The National Weather Service (NWS) issued a Tornado Warning.
• 12:11 PM: Lockport’s Nixle notification (our opt-in text message system) went out.
• 12:18 PM: Our team posted the warning here on our page.
• 12:35 PM: The severe weather sirens were manually activated for the community.
• 12:45 – 12:50 PM: The storm and high winds arrived in Lockport (roughly 10-15 minutes after the sirens).
The Logic Behind Siren Activation
It all comes down to how different warning systems are triggered, and how our team monitors local conditions. When severe weather hits, the NWS draws precise geographic boxes called "warning polygons" to pinpoint a storm's expected path. These warnings are usually designed to cover the next 15 to 60 minutes. Because storms can change direction or move erratically, forecasters purposely fan out the far end of the box to account for those unpredictable shifts. This means the further away we are from the storm when the warning first comes out, the wider the potential danger zone looks on paper. As the storm gets closer to Lockport, that path becomes much clearer and more defined.
• Wireless Emergency Alerts (WEA): Cell phone carriers broadcast alerts to devices physically located inside that NWS polygon. Individual reception times can vary slightly depending on how fast a wireless carrier processes and pushes the data stream across their network.
• County-Level Alarms vs. Lockport Threats: Traditional systems like NOAA Weather Radios warn an entire county based on broad digital codes. If sirens were triggered strictly based on county-wide warnings, Lockport's sirens would frequently go off for weather events miles away in Frankfort, Braidwood, Beecher, or Monee, creating "warning fatigue" where residents begin to ignore the alarms.
• How We Coordinate: While some modern siren systems are fully automated to activate by NWS polygons, Lockport's system is typically activated manually. Dispatch can activate the sirens on their own under certain immediate circumstances (such as a confirmed tornado on the ground), but usually, the decision is made by the Officer in Charge within the Police Department based on the real-time information they have.
• Watching the Approaching Storm: Our goal is to monitor severe weather as it tracks directly toward the Lockport area, rather than simply sound alarms for distant county-level events. On July 27th, we tracked the storm's progression toward us, triggering the sirens as dangerous high winds began impacting our neighbors (for example, Plainfield and Bolingbrook). Had we activated the sirens the moment the NWS polygon was first drawn at 12:10 PM, there would have been a 35-minute gap before the storm arrived. Gaps that large often cause people to let their guard down or assume it was a false alarm.
3 Critical Safety Reminders
Moving forward, we want to reiterate three important points for our community's safety:
1. Sirens are the Last Line of Defense: Think of outdoor sirens as the final safety net, not the first notification. By the time the sirens are activated, residents should have already received advanced warnings through NOAA radios, Nixle messages, and wireless cell phone alerts.
2. Sirens are for Outdoors Only: Outdoor sirens are strictly designed to warn people who are outside (in parks, on sports fields, or working construction) to seek immediate indoor shelter. They are not designed to pe*****te indoor walls or wake you up.
3. Maintain Multiple Alert Methods & Seek Information: Everyone should have redundant ways to get alerts. Start with a NOAA Weather Radio for broad county-wide events, and pair it with cell phone alerts. If you haven't already, you can sign up for our local opt-in text alerts by visiting nixle.us/city-of-lockport. When any alert happens, use that as a prompt to immediately tune in to local radar or weather broadcasts to see exactly where the storm is tracking relative to your home.
Thank you to the follower who brought this up! It gives us a great opportunity to talk about how we can all work together to build a safer, more informed community.
