Many technological systems are at risk due to space weather. These systems include, for example, satellites, the power grid, communication and navigation networks, and aviation. Extreme space weather might represent a great hazard to those infrastructures. This session is intended to provide insights in the magnitude, duration and frequency of extreme events, including, but not limited to, the following:

• Solar energetic particle events (flux and fluence)
• Electron enhancement events
• X-ray and radio bursts
• Geomagnetic storms
• High-speed solar wind

Those scenarios should define the intensity, spectrum, and duration of the relevant physical parameter that we should expect for different periods: 25, 50, 100 or 200 years. The idea is that the system operator can use the scenario proposed for the period of interest to assess the risk to the system.