Edit: Use the drop-down menus to select the storm that causes each environmental hazard.

Flash flood - (options: thunderstorm, tornado, hurricane)

Storm surge - (options: thunderstorm, tornado, hurricane)

Flash floods cause tornados.

Storm surges cause hurrricanes.

Explanation:

Don't blame on the answer, i'm not sure if it is right, I barely know about your subject and i just did research.

/what-causes-hurricanes-1203855

what-is-a-tornado-and-what-causes-a-tornado.html

what causes thunderstorms

it is actually thunderstorm and hurricane

Explanation:

answer; i believe the answer is hydraulic action;

enzyme speed up the reactions