Gonna post a few clips from our storm chase on 4/21/07, which includes the massive Cactus, TX tornado. Video quality is far from perfect, but you definitely get the gist. Be aware that there is some graphic language contained in the first clip.
Gorgeous mammatus.
vidcap of the tornado/meso.
Clip 1: remember, there's some rough language. (we were very excited to say the least lol)
Clip 2: maybe a minute or two has elapsed since the end of clip 1; the tornado emerges from the rain.
Clip 3: RFD winds estimated at near hurricane force impact us as the tornado crosses the road about a half mile or so in front of us. Note the two or three cars speeding past us, basically into the tornado (don't know if they knew what they were driving into).
Clip 4: An hour later, on our way back home, passing through Dumas with power out and tornado sirens blaring. Spooky. This is why we don't do night chases.
Like I said, video quality isn't excellent but it does capture some pretty exciting moments.