For more than three days, people in Clintonville, Wis., have woken up from sleep to a noise that some described as sounding like an explosion or distant fireworks.
What is it? No one knows. Geologists have ruled out earthquakes or explosions in old mines. City officials checked gas and sewer lines. The local military says they're not running any drills.
"In summary, it's crazy," Brian Niznansky, a meteorologist for Wisconsin's NBC26 station, said. "The craziest part is that no one has an idea, from the local officials to scientists, whether it's natural, manmade, a hoax, no one has any sort of idea what is going on. You can't rule out weather because we're in [a] historic heat wave."
Warm weather could potentially be to blame.
Lisa Kuss, spokesperson for the city, said the same, at a town meeting called on Tuesday to talk to residents about the disturbing sounds.
"It is a strong possibility that some natural phenomenon is occurring under the ground. We have discussed that both our strange winter weather and current very warm spring like weather, which is early, is extreme at best and somehow could be impacting our soils below the surface," Kuss said.
One theory about the noise is that the sound comes from the ground settling after ice in the ground quickly melted.
"If we've had a cold winter, and you get a good frost layer, 4 or 5 feet, then you get a huge warm up, you might get some cracking of the ground but our winter was very mild," Niznansky said.
"Cryogenic" noises, sounds related to freezing of the ground, are unlikely. Wisconsin had a warm winter. There were not many days with temperatures below freezing so that a thick frost layer could form. Temperatures were around 7 degrees above normal in January, almost 8 degrees above normal in February and 17 degrees above normal so far in March. The winter season's average temperature was 6F above normal.
"Over the last four days, Wisconsin had a dramatic increase in temperatures, from 20 degrees above normal to 35 degrees above normal," Margusity said. "Since Friday, the temperature has really increased rapidly. At the beginning of March, the temperatures were in the 30s. Wednesday was 81 degrees."
Margusity compared the ground warping to a bridge expanding and contracting in the cold.
"Between the wind, sunshine and humidity, you're warming the ground very rapidly, like a pan on the stove that warps because it gets hot so fast," AccuWeather meteorologist Henry Margusity said.
The 99th running of the Indianapolis 500 is set to take place on Sunday afternoon, but showers and thunderstorms may make an unwelcome appearance.
After a cooler and dry start to the holiday weekend, a surge of warmth will greet most Memorial Day cookouts and activities in the mid-Atlantic.
In a move to curb backlash surrounding water sourcing from drought-stricken California, Starbucks has pulled production of its Ethos bottled water out of the Golden State.
Memorial Day marks the unofficial start to summer, but the summer warmth set to dominate the Northeast next week will not be here to stay.
California farmers with century-old water rights in the San Joaquin River Watershed will no longer be able to draw water from the river as a result of the state's historic drought.
Dry weather will be the rule in Charlotte, North Carolina, this weekend, the site of this week's NASCAR race.
Liberal, KS (1933)
A powerful F4 tornado (winds 207-260 mph) hidden in a dust storm devastates the business district. 4 people were killed and 150 were injured. Tornado estimated to be 600 yards wide at times.
Sichuan Province China (1986)
More than 35,000 homes and 7,700 acres of crops were destroyed by a devastating hailstorm. Reports indicated that 100 people were killed and 9,000 injured. (Reports vary as to the exact date of the hailstorm.)
Atlantic City, NJ (1991)
Record high of 89 degrees after a record low of 38 degrees. Record lows were also set May 19,20, & 21st.