At least two tornadoes ripped across northern Texas Tuesday, flipping huge trucks like toys, tearing off roofs and grounding flights but apparently causing only minor casualties.One twister touched down in a parking lot full of tractor-trailers -- large trucks that move shipping-container sized cargos, and television images showed several containers twisting and flying dozens of feet up into the air. "It was raining and hailing like I said... and then all of a sudden, the rain and hail ceased... that's when we saw the tornadoes touch down," witness Jonathan Cook told CNN. The resident of Burleson said he dashed out of the bank when he saw hail the size of nickel coins start falling and leapt back into his truck to get it to the cover of a nearby gas station. "We were just under the gas pump awning, hoping it didn't come our way. We had a good visual of it, but we really had nowhere to go... we just had to run in the gas station." Texas resi...