What was a creeping barrage? What were its risks to the attacking soldiers?

A creeping bombardment, first employed at the Battle of the Somme, featured artillery fire going forward in stages only ahead of the advancing infantry. ... The plan demanded correct timing for both the heavy artillery and the infantry to function. Failure to do that would result in their own troops being killed by artillery.

geography

this is because warmer climates often don't get people sick from the flu and regions where it was often colder more people received the flu. hope this if you need more reasoning i am here to