A version of this article appears in print on Feb. 5, 2023, Section A, Page 21 of the New York edition with the headline: At Dallas Zoo, ‘One Gut Punch After Another’ in the Case of the ...

As the ice crystals form, they immediately fall out as snow from the clouds. A hole punch cloud observed on August 17, 2008 near Linz, Austria. Credit: H. Raab, NASA ...