The City of Ann Arbor Parks & Recreation Facilities are equipped with Lightning Detection Warning Systems, THOR GUARD. The THOR GUARD lightning warning system senses the "chance of lightning", not necessarily the occurrence of lightning. Therefore, the system activates even if there is no lightning is detected. The system senses the chance of lightning within about a 5-mile area around the main sensor, by measuring the static electricity between earth and sky.
All the systems are equipped with programmable timers so they are not supposed to alarm between 11:00 p.m. and 7:00 a.m. when there are no swimmers, golfers, or park users. They go off to warn park users and facility managers so they can take appropriate precautions (swimmers out of the pool, golfers off the course, etc.). The "Voice of Thor" air horns can be heard at an audible range of about 2000 feet from each detection system. Some locations such as the golf courses and Veterans Memorial Park have more than one, one is the actual main sensor, and the remote units just receive a signal from the main sensor transmitter. When the system detects lightning, there will be one long tone (approximately 30 seconds). The all clear will be three short horn blasts (approximately 10 seconds long).
The locations of the sensors are as follows:
Buhr Park
Pool roof
Fuller Park Pool
Huron Hills Golf Course
- Clubhouse
- Gallup Livery Roof
- Pump building on Huron River
- West side of Huron Parkway (500 yards south of the clubhouse)
Leslie Park Golf Course
- Clubhouse roof
- 6th hole, on the green
- 14th hole, on the green
Veterans Memorial Park
- Ice Arena roof
- Ball fields (light pole, 200 yards north of ice arena)
View a map of the lightning detection system (pdf format).
For more information about The THOR GUARD lightning warning system, visit their website @ http://thorguard.com/about.asp