WHAT WAS CLAIMED
Tropical Cyclone Alfred has been artificially created using HAARP or chemtrails.
OUR VERDICT
False. These phenomena have no effect on the weather.
AAP FACTCHECK - As Cyclone Alfred threatens millions of people in two Australian states, false claims that humans created the storm are swirling online.
Social media posts are incorrectly claiming the High-frequency Active Auroral Research Program (HAARP) in Alaska or "chemtrails" helped spawn the tropical storm.
Experts have previously told AAP FactCheck there's no evidence the Alaskan facility can affect weather or that "chemtrails" exist.
Millions of people are preparing for Alfred to make landfall late on Thursday or early Friday between Queensland's Sunshine and Gold coasts, the first time a cyclone has hit the southeast coast since 1974.
One Facebook post featuring a screenshot of a news graphic showing a cyclone tracking map bears the caption: "HAARP & weather warfare against the people."
Another post shares an image of a comment declaring: "WAKE UP AUSTRALIA!!! This is being done deliberately this severe weather event is being manipulated. This is geoengineering weather manipulation HAARP Chemtrail Spraying Nexrad Dew and EMF ... This is a deliberate attempt to cause devastation destruction pain death and homelessness."
However, any suggestion the cyclone was artificially generated is incorrect.
AAP FactCheck has debunked several false claims about HAARP's ability to control the weather in relation to several other extreme weather events.
HAARP was built by the US military but is operated by the University of Alaska Fairbanks.
The facility transmits radio waves into the ionosphere, about 100 kilometres from the earth's surface, but atmospheric scientists have confirmed that its functions cannot affect weather.
Bruce Ward, an ionosphere researcher at the University of Adelaide, previously described the HAARP weather control claim as a conspiracy theory that had "been doing the rounds for 30 years".
"At no stage have I seen a claim that is backed by even a modicum of scientifically credible theory," Professor Ward told AAP FactCheck.
Fred Menk, an ionosphere and magnetosphere expert from the University of Newcastle, previously explained that HAARP's ionosphere activities do not affect weather formation in the stratosphere or the troposphere, which are many kilometres closer to ground level. "Weather at ground level is driven by geophysical effects, mostly solar heating, into the neutral atmosphere much nearer the ground," Professor Menk told AAP FactCheck.
Other Facebook posts blaming Cyclone Alfred's formation on "chemtrails" are referencing a conspiracy theory that claims long white clouds visible behind aeroplanes at high altitudes are hazardous to human health.
AAP FactCheck has previously debunked those claims, finding that "chemtrails" do not exist.
Experts said the formations are non-hazardous condensation trails, or "contrails", formed by water vapour and particles emitted from a jet engine's exhaust.
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