What maximum wind speed classifies a storm as a tropical depression?

A storm is classified as a tropical depression when it has maximum sustained winds of 38 MPH or less. This definition is part of the scale used to categorize tropical cyclones, which begins with a tropical depression and progresses to a tropical storm and then to a hurricane.

In this classification, a tropical depression is characterized by weak circulation and low wind speeds, indicating that the storm is in its early stages of development. It may not yet have the organized structure and intensity that would classify it as a tropical storm, which requires sustained winds of at least 39 MPH. Understanding this classification is crucial for marine science technicians as it affects preparedness and response strategies in areas prone to tropical weather phenomena.