This article is a year old, but I thought it was interesting:
OSHKOSH, Wis. (WFRV) - Country USA is in full swing and besides the party atmosphere, those in the crowds also have to contend with unpredictable weather.
"Our concern is the campers at night when severe weather does approach," explained Winnebago Co. Emergency Management Director Linda Kollmann.
That's one of the reasons Kollmann said the county decided last year to purchase a portable siren. It will sit on the Country USA campgrounds throughout the festival, ready to alert concert-goers if severe weather approaches.
"Because it is out in the country there really isn't a lot of tornado siren coverage in that area," she said. "So we thought we'd purchase it because we have so many large events here in Winnebago County."
It's also been used at Rock USA and EAA.
The decision on whether to sound the siren comes from the National Weather Service and those on site tracking the storms.
"For either evacuations of sites or incoming bad weather, tornadic weather that we see coming in, we have a fairly strong system," explained Country USA's Dan Liebhauser.
Kollmann said the siren can also be used in other parts of the county if any of the permanent sirens ever goes down.
"We can broadcast missing children information, for a large event like that we think it's really important that we can communicate out to the campground," added Kollmann.
She said just one more way to keep these country fans safe and sound.
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So it seem they bought an E-Class siren to keep people safe at the rock concert, and it's also portable. Link to the video here..: http://wearegreenbay.com/1fulltext-news?nxd_id=137292