Big Waves (IMAGE) Columbia Climate School Caption An idealized illustration of giant meanders in the global jet stream known as wave-4 patterns, which are bringing extreme winter cold and/or precipitation (blue areas) to parts of North America and Europe. Credit Graphic by Kai Kornhuber. Usage Restrictions Credit must be given. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.