Drag the Kp slider to watch Earth's aurora belt widen and NOAA's real G1-G5 storm-severity scale light up, then jump straight to the real May 2024 G5 superstorm.
NOAA's G-scale turns the 3-hour Kp geomagnetic index into a public-facing severity label: Kp=5 is G1 (Minor), rising to Kp=9 as G5 (Extreme). The May 2024 "Gannon storm" reached Kp=9 (G5), the strongest geomagnetic storm since the October 2003 Halloween storms.
Drag to orbit and scroll or pinch to zoom. For the light-emission mechanism behind aurora itself, see the Aurora 3D Explorer; for one specific historical superstorm, see the Carrington Event 3D Explorer; for the field's static structure, see the Earth Magnetosphere 3D Explorer.
Kp-Index Geomagnetic Storm Scale 3D Explorer
This browser explorer maps the real 0-9 Kp geomagnetic index onto NOAA's G1-G5 storm-severity scale, widens an illustrative aurora belt as the slider rises, and drives a synthetic magnetometer-style trace so a reader can feel how much stronger a G5 storm reads than a quiet Kp of 2 or 3.
The Kp index is a 3-hour planetary geomagnetic-activity index on an integer 0-9 scale, introduced by Julius Bartels in 1949. The official, finalized Kp is computed by GFZ Potsdam as the normalized average of the local K-index from 13 ground magnetometer stations at geomagnetic latitude 44-60 degrees north or south; NOAA's Space Weather Prediction Center separately publishes a real-time estimated Kp from a subset of ground magnetometers ahead of the finalized GFZ value. NOAA maps five Kp thresholds onto its G-scale: Kp=5 is G1 (Minor), Kp=6 is G2 (Moderate), Kp=7 is G3 (Strong), Kp=8 is G4 (Severe), and Kp=9 is G5 (Extreme); Kp 0-4 sits below the G-scale with no storm level assigned. Aurora visibility widens toward the equator as Kp rises: at low Kp it is generally confined to the high-latitude auroral oval near the poles, around Kp 7 it can reach mid-latitudes, and at Kp 8-9 it can become visible from low latitudes.
- Drag the Kp slider (0-9) to change the storm-severity level
- Watch the aurora ring widen and the outlined cell move across the 0-9 grid
- Click "Jump to May 2024 Superstorm (G5)" to load the real G5 case
- Read the synthetic magnetometer-style trace widen with the storm level
- Drag to orbit, scroll or pinch to zoom
- Runs fully in the browser with the vendored three.js engine - no account, no upload
| Kp value | NOAA G-scale | Note |
|---|---|---|
| 0-4 | Below G-scale | No storm level assigned |
| 5 | G1 Minor | - |
| 6 | G2 Moderate | - |
| 7 | G3 Strong | Aurora can reach mid-latitudes |
| 8 | G4 Severe | - |
| 9 | G5 Extreme | May 2024 "Gannon storm": Dst min -412 nT, Ap max 271, aurora reported as far south as Alabama and Northern California - the strongest storm since the October 2003 Halloween storms |
For the light-emission mechanism behind aurora itself, open the Aurora 3D Explorer. For one specific historical superstorm, open the Carrington Event 3D Explorer. For the field's static structure, open the Earth Magnetosphere 3D Explorer. For a similarly shaped classification-scale page in a different domain, see the Torino Impact Hazard Scale 3D Explorer.
Everything renders on your device with WebGL. The 3D engine loads once (about 0.7 MB) and is cached.
This is an educational approximation - the field arcs, aurora-ring size, and magnetometer trace are illustrative teaching cues, not a computed field model or a live space-weather feed. The Kp thresholds, the G-scale mapping, and the May 2024 case figures are the real NOAA/USGS-published values.
Frequently Asked Questions
What is the Kp index?
A 3-hour planetary geomagnetic-activity index on an integer 0-9 scale, introduced by Julius Bartels in 1949. The official value is computed by GFZ Potsdam from 13 ground magnetometer stations at geomagnetic latitude 44-60 degrees; NOAA separately publishes a real-time estimate.
How does Kp map to NOAA's G-scale?
Kp=5 is G1 (Minor), Kp=6 is G2 (Moderate), Kp=7 is G3 (Strong), Kp=8 is G4 (Severe), and Kp=9 is G5 (Extreme). Kp 0-4 sits below the G-scale with no storm level assigned.
What happened during the May 2024 superstorm?
The "Gannon storm" reached Kp=9 (G5 Extreme), a minimum Dst of -412 nT and a maximum Ap of 271 - the strongest geomagnetic storm since the October 2003 Halloween storms - with aurora reported as far south as Alabama and Northern California.
Does higher Kp always mean aurora further south?
Generally yes: at low Kp, aurora is usually confined to the high-latitude auroral oval near the poles; around Kp 7 it can reach mid-latitudes; at Kp 8-9 it can become visible from low latitudes, as in May 2024.
Is the magnetometer trace on this page real data?
No - it is a synthetic, illustrative pattern whose swing widens with the picked Kp value, not a live or historical magnetometer feed.
How is this different from the Aurora, Carrington Event, and Earth Magnetosphere pages?
The Aurora page explains the light-emission mechanism itself. The Carrington Event page covers one specific 1859 historical storm. The Earth Magnetosphere page shows the field's static structure. This page is the numeric G1-G5 severity scale, compared across Kp values and the real May 2024 case.
Is the on-screen field and aurora geometry physically accurate?
No - the field arcs, aurora-ring size, and magnetometer trace are illustrative teaching cues, not a computed field model or a live space-weather feed. The Kp thresholds, G-scale mapping, and May 2024 case figures are the real NOAA/USGS-published values.