Jet streams are relatively narrow bands of strong wind in the upper atmosphere, typically occurring around 30,000 feet, and blowing west to east. Their normal flows lead to week-to-week weather variations, modulated in the mid-latitudes by ridges and troughs in the jet stream. A high-pressure ridge, for example, produces clear, warmer weather conditions; a trough is typically followed by stormy conditions. Together, these form waves in the jet stream that can stall as the waves grow and become more amplified, causing “stuck” weather patterns that produce longer storms and heat waves.

New research published in Nature Communications describes observations linking increased warming at high latitudes and the ever-decreasing snow cover in North America to these stalls in atmospheric circulation.