Drought
Information
One of the main methods used
to calculate drought indices is called the Palmer Drought Severity
Index (PDSI), which was developed in the 1960's and uses temperature
and rainfall information in a formula to determine dryness.
The PDSI is most useful in determining long-term drought information
and is expressed using negative numbers. The scale for the
PDSI is as follows: 0 = Normal Conditions, -2 = Moderate Drought, -3
= Severe Drought, -4 = Extreme Drought. The PDSI is an
acceptable calculator, because it is standardized for local
conditions, thus making it applicable to any part of the country.
Below are links to the National Drought Integrated Drought
Information System, National Climatic Data Center (NCDC) Indicator
Maps for Drought Monitor and Soil Information, and the National
Drought Mitigation Center.
National Integrated Drought
Information System
NCDC U.S. Drought Monitor System
National Drought
Mitigation Center
Office
(301) 405-7223
Fax (301) 314-9482
Maryland State Climatologist Office