Hams have a history of stepping up during emergencies or natural disasters and providing communications when other means such as cell phones and landlines are down and not operable. To do this hams need to know how to set up their equipment and get “on the air” as quickly as possible.
POTA is a program where hams setup in National or State Parks as well as wildlife areas and State forests etc. and make contacts (called QSOs) with other hams. The ham setting up in the park is referred to as an “activator” and the hams he makes contact with are called “hunters”. Setting up portable operations like this is great practice for emergency communications.
QRP is the term we use for operating with limited power. That means 5 watts or less for CW (think Morse code) and a maximum of 10 watts for other modes (think voice communications).
For more information you can check out the ARRL website or the Parks on the Air website.