Scientists might predict the following outcomes due to solar flares:
- Electrical systems in satellites will fail.
- Radio navigation systems and global positioning systems will be inaccurate.
- High-frequency radio waves used for radio communication will be blocked.
- Power grid operations will go offline.
All of the provided responses are potential impacts of solar flares, but if you need to select just one or the most direct response, "high-frequency radio waves used for radio communication will be blocked" is a common and immediate effect observed during solar flare events.