Wonder Woman is one of the strongest characters in DC Comics. Meanwhile, Storm is an Omega Level mutant who's abilities, including being able to control the weather, are extraordinarily powerful. But, when the two heroes fought against each other there was only one victor.
The 1996 crossover DC vs. Marvel had some of the biggest heroes from each publisher fight each other with the winner being decided via fan voting. Batman fought Captain America, The Flash had a speedster battle against Quicksilver, and Wolverine took on Lobo in a battle between unkillable brutes. One of the premier matchups featured Wonder Woman and Storm as Princess Diana of Themyscira battled the former Queen of Wakanda.
Wonder Woman and Storm's fight starts out with a bang, as Diana picks up Mjolnir after Thor drops it during a battle with Shazam. She is deemed worthy and transforms into a superpowered God. However, when Storm refuses to yield despite Wonder Woman's upgrade, Diana decides to drop the hammer in order to have a fair fight. The match begins with Wonder Woman initially having the upper hand, as she swings Storm around in the air with her pure strength. Her advantage doesn't last, as Storm uses lightning to electrocute Wonder Woman in the rain. "Forgive me, sister," Storm states as Wonder Woman falls to the ground.
Perhaps, Wonder Woman should have kept Mjolnir during the fight. While she's incredibly strong, having the power that comes with being worthy would have certainly come in handy against Storm. But, dropping Mjolnir in order to make it a fair fight was an honorable move all things considered. Wonder Woman didn't have to do that, but she didn't want an unfair advantage. Although, Storm getting the best of Diana isn't a surprising result. She's an Omega Level mutant who could probably tango (and win) just about anyone on the list. It's fair to assume no matter who she faced, she was going to have a serious chance at winning.
The fans, in this case, seemed to get things right. That's not a knock against Wonder Woman - she's an extremely strong hero who would have won many other potential DC/Marvel battles. However, against Storm, it was always going to be an uphill battle. She put up a good fight, but Storm earned a clear victory in this one.