It's unusual these days to see a place of business that doesn't take debit or credit cards. In the world of commerce, they are second nature. Many millennials use credit and debit cards almost exclusively.

If something wipes out the power grid like a 9.0 earthquake or the blackout that struck the east coast of the U.S. in 2003, kiss that goodbye. Some businesses in that kerfuffle closed up shop because their cash registers didn't work.

You'd better have cash to help you make it through that emergency.

If there is no power, there are no ATMs. If there is no cellular or satellite network, there are no working debit or credit card machines. And it could be that way for weeks depending on how badly the infrastructure is damaged.

"A lot of millennials, they carry no cash whatsoever. They're living in this electronic world where they put everything on the card. So having some cash available, both coins and bills, would be good," emergency response veteran Eric Holdeman said.

You should have some cash in both your home and car emergency kits. Your three-day kit is to get you safely from A-to-B, so maybe enough for some gas (if gas pumps are even working) and for some food or water from the store.

Make sure you have a selection of denominations: Ones, fives, 10s, 20s, and coins. Cash registers may not be working, so stores may not be able to make change.

Join KING 5’s Disaster Preparedness Facebook group and learn how you and your community can get ready for when disaster strikes.