About the Atlas

Purpose

The modules were made for university lectures in electrical engineering. Each one takes a single phenomenon and shows it as a sequence of stages that can be played, paused and inspected from any angle, with a short explanation for every stage.

The Atlas will grow: further modules on direct and indirect lightning strokes and on protection measures are in preparation. Addresses of published modules will not change, so they are safe to link from slides and course pages.

Author

The Atlas is written and maintained by Fabio Tossani.

Corrections, comments and requests are welcome: info@thelightningatlas.com.

Scope of the models

Part I · From Preliminary Breakdown to Return Stroke

A conceptual educational visualisation, not a physical discharge simulation. It shows a downward negative cloud-to-ground flash, the most common type of cloud-to-ground lightning, up to its first return stroke: there are no subsequent strokes or continuing current, and upward lightning, which starts from tall structures, and positive flashes are not covered. Distances, channel widths, colours and stage durations are schematic, and the current plot is a dimensionless illustrative envelope. Every stage uses a stretched teaching time scale.

Part II · From Lightning Stroke to Backflashover

Currents and voltages replay an EMTP simulation of a 735 kV line struck at a tower by a first negative stroke with a CIGRE waveshape, 100 kA peak. EMTP provides values at the terminals of each element; where the module shows a quantity along a tower or a span, that reconstruction is described in the module itself. The time scale is slowed for teaching.

How to cite

If you use the Atlas in teaching material or in a publication, please cite it as:

F. Tossani, The Lightning Atlas, 2026. https://thelightningatlas.com

Licence

Unless stated otherwise, the content of this site (texts, figures, animations and interactive modules) is © 2026 Fabio Tossani and is licensed under the Creative Commons Attribution-NonCommercial 4.0 International licence (CC BY-NC 4.0).

• You may use, share and adapt the material for teaching, study and research, provided that you give appropriate credit and indicate any changes.
• You may not use it for commercial purposes without permission; to ask for it, write to info@thelightningatlas.com.

The modules include open-source software that keeps its own licences: three.js (MIT), KaTeX (MIT) and the KaTeX fonts (SIL Open Font License 1.1). See the third-party notices.

Privacy

This site sets no cookies and shows no advertising. It consists of static files hosted on Cloudflare; like any web host, Cloudflare processes technical request data such as IP addresses in order to deliver the pages.

Visits are counted with Cloudflare Web Analytics, which uses no cookies and does not follow visitors from one site to another. It reports aggregate figures only, such as page views, referring sites, countries and page-loading times.

The modules remember two display choices in your browser's local storage: whether the scenery is shown in Part II, and whether you have closed the hint to rotate your phone. They stay on your device and are not sent anywhere.

For any question about privacy, write to info@thelightningatlas.com.