mesocyclone tornado hook echo wall cloud supercell thunderstorm super outbreak rocky mountains rear flank downdraft radar national weather service la nina inflow bands hail gustnado gulf of mexico fujita scale enhanced fujita scale clash of air masses beavers tail arctic intensity early warning system earth’s crust seismograph north american plate epicenter bow echo magnitude propagation velocity tvs liquefaction body wave tsunami richter scale seismic wave p-wave earthquake
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