Grant admitted he was "massively shocked" by Storm's death and is absolutely "devastated for her family and friends."
"We were lucky to have Erin on season 12," Grant toldEntertainment Tonight. "She was genuine, self-assured, beautiful and hilarious."
Storm was flying a private, light-sport and weight-shift control aircraft when it dropped from the sky shortly after takeoff around noon. The cause of the accident remains unclear.
Firefighters quickly arrived at the scene, where they discovered flames, scattered plane pieces and a woman already in full cardiac arrest. The pilot from Venice, CA, was rushed to a nearby trauma center, where she later passed away.
Joshua Daniel, a friend of Storm's, posted the following message on Facebook: "I'm super sad to say that my friend Erin Storm passed away in a light aircraft accident. Erin was a beautiful person inside and out, and that anyone who knew her would tell you the same."
He added, "She was always a nice, caring person who beat to her own drum. She was loved by many people and will be dearly missed -- God speed Erin, the world has just experienced a great loss."
Another friend, Christiana Marie, wrote on social media, "It is with the heaviest heart I've ever had to be posting this. My sweet Erin Storm You have changed my life in many ways and showed me what TRUE BEST FRIENDS are all about!!! Heaven just received the most incredible angel in the world."
Storm, a former Pacific Blue Air pilot, made it to the Top 12 on The Bachelor. She was billed as a 33-year-old hot dog vendor during her appearance on the show in 2008.
"Somehow you knew from the first minute of being with her that Erin could pretty much go and do anything," Grant told ET. "On my season her occupation was listed as hot dog vendor... which surprised me a little bit. From talking to her, it soon became clear she was a smart, entrepreneurial cookie."