Aurora Substorms — It Comes in Pulses — Aurora Guide

Aurora Substorms — It Comes in Pulses

Even on a perfect aurora night, the display rarely stays on continuously. It comes in bursts called substorms — sudden intensifications that last 20 to 60 minutes, often followed by quiet periods of 30 minutes to an hour before the next one fires.

A substorm happens when energy that has been building up in Earth's magnetic tail suddenly snaps and releases — like a stretched elastic band. The result is a rapid brightening, often starting as a quiet arc low on the horizon that suddenly erupts into dancing curtains overhead.

Typical Aurora Night — What Actually Happens
quiet
quiet
quiet
Activity over a typical 4-hour aurora night — quiet gaps between bursts are normal
Substorm lasts
20–60 minutes of active display, sometimes with rapid curtain movement
Quiet gap lasts
30 minutes to 2 hours — the sky may go dark between events
Per night
2–5 substorms on an active night. Peak activity is usually between 10pm and 2am local time
The most common mistake: Going outside for 15 minutes, seeing nothing, and going back to bed — only to miss a spectacular display at midnight. Stay out for at least 90 minutes on a forecast aurora night. Bring a warm drink.
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