Wildly improbable conspiracy theories about Hurricanes Helene and Milton have spread largely unchecked on social media. The storms were engineered to clear the way for lithium mining. They were sent to help the Democrats in next month’s election. They were formed by weather-controlling lasers.

The claims persist despite attempts by scientists and government officials to debunk them with evidence. They survive all calls to reason.

The falsehoods, which have been circulating on X, TikTok, YouTube and other platforms, can resemble the conspiracy theories that plague modern American politics. Prominent figures are pushing them, citing unrelated, misleading or outdated evidence.

But the risks are often more immediate. Online climate-related conspiracy theories can quickly cause damage offline, disrupting emergency communications and recovery efforts. Officials have said this week that the disinformation about Hurricanes Helene and Milton was making relief workers a target, and the American Red Cross warned that the outlandish claims could prevent survivors from seeking help.

“If they’re telling you that the government is responsible for the disaster, that doesn’t help you at all in getting ready for it,” said Jose E. Ramirez-Marquez, an associate professor of systems engineering at Stevens Institute of Technology and a co-author of a journal article this month on how hurricane-related information traveled through X.

The increasing frequency and devastating power of major storms, heat waves, wildfires and other weather-related catastrophes tend to elicit an especially strong emotional response, allowing climate denialists, lobbyists for the oil and gas industry and rumormongers to exploit people’s concern and confusion.