Disasters and tragedies have long been a source of conspiracy theories. But when devastating flash floods hit Texas over the Fourth of July weekend, far-right conspiracies over cloud seeding and weather manipulation spread within a matter of hours. The floods killed at least 135 people, including children who were staying at an all-girl summer camp along the Guadalupe River. Extremism reporter Ben Makuch explains more behind these conspiracy theories, while Guardian US environment reporter Oliver Milman tells us what really happened