Negative polarity CH HSS sparks G1 geomagnetic storm

Negative polarity CH HSS sparks G1 geomagnetic storm

Earth is under the influence of a recurrent, polar-connected coronal hole which has sparked G1 (Minor) geomagnetic storming today. Unsettled to active conditions, with G1 storming likely, are expected to continue through March 2.

Geomagnetic K-index of 5 (G1 - Minor geomagnetic storming) threshold was reached at 10:36 UTC on March 1, 2017. Area of impact is primarily of 60 degrees Geomagnetic Latitude.

Under G1 conditions, weak power grid fluctuations can occur, minor impact is possible on satellite operations and aurora may be visible at high latitudes.

SWPC forecasters said unsettled to active conditions are expected, with G1 (minor) geomagnetic storming likely, on March 1 and 2 as a negative polarity, coronal hole high speed stream (CH HSS) becomes geoffective. Mainly unsettled to active levels are anticipated on March 3 as the CH HSS begins to subside.

Solar wind speeds ranging from 600 - 700 km/s are anticipated based on earlier observations from STEREO-A.

Kp-index March 1, 2017Geoeffective coronal hole February 28, 2017Detected coronal holes on March 1, 2017

SWPC Alerts

Space Weather Message Code: ALTK05
Serial Number: 1063
Issue Time: 2017 Mar 01 1036 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2017 Mar 01 1036 UTC
Synoptic Period: 0900-1200 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

NOAA Space Weather Scale descriptions can be found at

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

Featured image: Geoeffective coronal hole on February 28, 2017. Credit: NASA/SDO/AIA, LMSAL

Register/become a supporter

Support us AD-FREE

Your support is crucial for our survival. It makes this project fully self-sustainable and keeps us independent and focused on the content we love to create and share. 

Monthly subscription

Subscription options

Yearly subscription

Subscription options

You'll receive your ad-free account for 20x faster browsing experience, clean interface without any distractions, ability to post comments without prior editorial check, all our desktop and mobile applications (current and upcoming) ad-free and with the full set of features available, a direct line of communication and much more. See all options.

Tags: g1 storm


No comments yet. Why don't you post the first comment?

Post a comment

Your name: *

Your email address: *

Comment text: *

The image that appears on your comment is your Gravatar