Why so many tornadoes hit tornado alley / Mangawhai tornado: Community rallies to aid devastated homeowners / Mangawhai tornado: Huddled in the hallway as wind roared through the house / 'Dramatic tornado' sweeps through Gloucestershire town as thunderstorms cause disruption / I'm a real life 'Twisters' storm chaser in apocalypse-proof Dominator truck - I survived the biggest tornado ever / What do storm chasers really do? Two tornado scientists explain the chase and tools for studying twisters / Students crisscross tornado alley, chasing storms, sharing data, learning lessons / Tornado alley appears to be expanding as deadly storms hit U.S. / If Canada's tornado alley is shifting east, how can we better prepare? / 'Tornado-like' storm devastates town in South Africa