What type of ice is characterized by a rapid and significant accumulation rate requiring immediate response?

Severe ice is characterized by a rapid and significant accumulation rate, which poses critical challenges to aircraft performance and safety. This type of icing can accumulate quickly on critical surfaces of an aircraft, such as wings and tail surfaces, leading to adverse effects such as increased drag, reduced lift, and altered handling characteristics.

The immediate response to severe icing conditions is necessary to mitigate these risks, which may include activating de-icing systems or seeking to change altitude or route to avoid the hazardous conditions. Understanding the severity and potential impacts of various types of icing is crucial for pilots and air traffic controllers to ensure safety during flight operations.

In contrast, lighter forms of ice accumulate at slower rates and generally do not require as immediate a response, allowing for more time to manage and navigate through such conditions.