Use maps and census data to determine the population severely affected by the disaster. Small-scale or local disasters affect up to 50,000 people. Medium and large-scale disasters affect between 50,000 and 500,000 residents. Catastrophic disasters affect over 500,000 individuals.  Contact health agencies and hospitals to find out the number of deaths immediately related to the disaster. If the number is under 5,000 the disaster qualifies as small scale. Numbers between 5,000 and 20,000 indicate medium and large-scale disasters. Immediate deaths over 20,000 qualify the disaster as catastrophiC