I moved into new home and we got a heavy rain. Thousands of white grubs surfaced and are crawling all over yard, driveway and sidewalk. Will they die from exposure, or the water, or do I need some insecticide? Also, will they try to go back into the soil?
I'm sure the grubs will attempt to return to the soil. Your first job is to find out what kind of grubs they are - you never want to apply any insecticide without knowing exactly what you're attempting to control. The best thing is to capture a few of them and have them identified, either at a plant store or the county extension service (by far the best source of information.) This link will help you find the nearest office:
This articles is about Japanese beetle grubs, which may or may not be what you are seeing. But the article may give you some insight: https://www.gardeningknowhow.com/plant-problems/pests/insects/get-rid-of-grub-worms.htm