Residents of Aurora may hear warning sirens as part of a system test.

The City of Aurora has over 50 outdoor emergency warning sirens placed throughout the city. They are there to warn people and alert them to get inside if there is an emergency situation such as "a tornado or hazardous material spill that may affect the community or whole city," states the official site.

Aurora conducts audible tests of the sirens two times a year. This year, the first test occurred on March 10 at 11:30 a.m., with the second occurring today, November 10, at 11:30 a.m.

If you want to hear what the siren sounds like, there's an example here.

In the event of an emergency, the sirens make a loud, three-minute wailing sound that signals everyone to take shelter indoors immediately. There is no longer an all-clear siren that signals it's safe to move on. Residents are advised not to go outside to find the source of the emergency, instead, they are asked to turn to local television, radio, social media, or television for information.

Do NOT call 911 if the sirens go off, unless you need to report a fire, or damage due to a tornado, severe injury, etc. These lines need to be kept open and available for medical emergency calls. The sirens will sound if there is a National Weather Service tornado warning and a tornado has been spotted within city limits.

Denver is part of Colorado’s Tornado Alley and ranks 10th in the country as far as active tornadoes. Last year, we saw high tornado activity in the state, so having these kinds of warning systems in place can truly save lives when disaster strikes.

Did you know the City of Aurora had so many emergency sirens? Do you remember the last time they went off for a true emergency in the city? Give us the scoop in the comments.