Strangers helping strangers

>>> we want to end the broadcast where we started tonight, that path of destruction from this week's tornadoes. the aftermath is just awful and a lot of people just don't know where to begin. but something else is happening there, as it always does, thankfully. neighbors are showing up and digging in and they are making a difference without ever being asked. their story from nbc's john yang in harveyville , kansas.

>> they're asking you to check in at mission valley school --

>> reporter: when the call went out in america's heartland. volunteers answered by the hundreds. strangers helping strangers . ron snod dy is a retired carpenter and one-time rodeo rider. you're working hard out here. missy is taking time off from her job as a nurse at a topeka hospital.

>> doesn't matter whether you know them or not. it's a small town . it's what you do.

>> reporter: retired schoolteacher mike worked alongside. does that make any difference that this is a stranger's house you're working on?

>> no, because someday i may need it and he may come up there and help me.

>> the sound of help.

>> reporter: some were armed with chainsaws, shovels and front-loaders. others used just their sweat and muscle to clean up this town where almost half the houses are rubble. volunteers have poured into harveyville from across the region, even from out of state. there are so many that they've tripled the town's population, normally less than 300 people.

>> i'm just overwhelmed.

>> reporter: those here struggling to pick up the pieces of their lives are grateful.

>> the response that we've had, it's just been tremendous.

>> reporter: some just couldn't find the words. when you see all these people driving in --

>> it's --

>> reporter: as an army of strangers pulls together to form a community of caring. john yang , nbc news, harveyville , kansas.