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Rare G4 alert for geomagnetic storm could lead to GPS outages

A cropping systems specialist says that major disturbances in Earth’s magnetosphere will continue to disrupt GPS navigation for farmers into next year.

“We’re still in what space scientists call the battle zone.”

Terry Griffin with Kansas State University says geomagnetic storms occur about every 11 years after solar sunspot maximum and can impact GPS signals. “That means for the rest of the 2025 season – planting, summer, mid-season applications and harvest – we will still be vulnerable to solar activity even into the spring of 2026.”

Geomagnetic storms are the result of several coronal mass ejections (CME) of solar material and strong magnetic fields that erupt from the sun. 

He tells Brownfield any outage could have an impact. For example, “It’s the automated section control, which is used on planters, sprayers and spray nozzles to turn off sections of the boom. Without GPS accuracy, that technology is essentially ineffective.”   

Most recently, the Space Weather Prediction Center issued a rare G4 alert for Sunday and Monday, and Griffin says the duration of an outage depends on the storm’s severity.  “If we’re in the G2 stage, the length would be minutes and wouldn’t be noticeable. If we’re in G4 or G5 it will likely be hours or even days.”

He says he expects significant relief by next summer.

Terry Griffin: