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Pyrocumulus clouds tower tall above a wildfire in these photos taken last week from an Oregon National Guard F-15C.

Most cumulus clouds form when the sun-warmed surface heats air, causing it to rise and carry moisture upward where it condenses to form clouds. In pyrocumulus clouds, the driving heat is supplied by a forest fire or volcanic eruption. The hot, rising air carries smoke and soot particles upward, where they become nucleation sites for condensation. Pyrocumulus clouds can be especially turbulent, and the gusting winds they produce can exacerbate wildfires. In some cases, the clouds can even develop into a pyrocumulonimbus thunderstorm with rain and lightning.

x6gB5 TIL that Kongō Gumi, an Osaka-based construction firm founded in the year 578, is the world's oldest documented company.
nGMo TIL half of the US population lives in 9 states (CA, TX, FL, NY, IL, PA, OH, GA, NC)
9YvpD TIL that Thomas Jefferson once met Mozart to commission a piece for his wife. However, he was put off by Mozart's personality, and ended up not going ahead with the idea.
Brydr TIL Ronald Reagan's pet name for his wife Nancy was "Mommie Poo Pants"
9YPm7 TIL that Sweden tries to ward off Russian submarines from violating its maritime borders by lowering a neon sign depicting a thrusting 'gay' sailor underwater. The sign also sends a message in Morse code which says, "this way if you are gay".