When the volcano color code changes, a Volcano Observatory Notificatio
Detailed Description
AVIATION COLOR CODES
When the volcano color code changes, a Volcano Observatory Notification for Aviation (VONA) is issued.
Sources/Usage
Public Domain.
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
