cheryl mcwilliams was diving in the gulf of mexico 30 miles off the coast of florida when she had a chance encounter with a whale shark. mcwilliams says she wasn't scared and reached out and touched the shark. >> it's like seeing a school buss underwater. it's just enormous. you're just awe-struck. >> williams says sharks typically get a bad wrap and many are endangered. she hopes this video will improve the shark's image. >> we need to point out that that shark is not car nif vous. rous. >> even so, i hope somebody else improved its image, no matter what he eats. so some more fog in our future? it was pretty erie this morning. >> and kind of awful this morning, too, really early on. so tomorrow morning, the fog is not going to be as thick. but we're going to have something else to deal with tomorrow morning. that is rain. we'll head out. where he've got a mostly cloudy sky. the visibility not really all that bad throughout the area. yesterday at this time, they were down under a maf mile. culpepper right now, doing pretty good throughout the entire area. taking a look at the visibility be

>> reporter: jim, cheryl mcwilliams said at first she thought it was a boat. but that didn't make any sense. soon it became clear it was a shark. it was swimming right toward her. 75 feet beneath the surface. fortunately for her, whale sharks feed on plankton, not pele. >> that's me breathing. because i'm swimming so hard. >> reporter: the diver you see in this incredible video is cheryl mcwilliams. she had an unexpected close encounter with a whale shark off the florida coast last month. what was your initial thought when you saw it? >> oh, my goodness. look, it's a whale shark. how amazing is this, you know, how lucky. >> reporter: mcwilliams is a fairfax county firefighter and dive instructor. she was on a dive off the gulf of mexico 30 miles off the coast. she was exploring a shipwreck on an artificial reef. >> it's like almost seeing a school bus underwater. it's 25 feet long. and it's just enormous. you're just -- you're awe-struck. >> reporter: mcwilliams said she was not scared. she has nearly 20 years of diving experience. she recognized the polka dot

. >> reporter: the diver you see in this incredible video is cheryl mcwilliams. she had an unexpected close encounter with a whale shark off the florida coast last month. what was your initial thought when you saw it? >> oh, my goodness. look, it's a whale shark. how amazing is this, how lucky. >> reporter: mcwilliams is a fairfax county firefighter and dive instructor. she was on a dive in the gulf of mexico 30 miles off the coast. she was exploring the mohawk shipwreck on an artificial reef when the female whale shark made a visit. >> it's 25 feet long. it's just enormous. you're awe-struck. >> reporter: mcwilliams said she was not scared. she has nearly 20 years of diving experience. she recognized the polka dotted creature as being a whale shark, the largest fish in the world. >> i actually touched her tail as she was swimming past me one time. they're pretty interesting. they feel kind of like sandpaper almost. >> reporter: a newspaper reporter took this picture as the whale shark swam toward her. she grabbed some of her own photographs and video as well. th