Small trees in leaf begin to sway; crested wavelets form on inland waters.
On the sea:
Moderate waves, taking a more pronounced long form; many white horses are formed.
Power systems: High-latitude power systems may experience voltage alarms,
long-duration storms may cause transformer damage.
Spacecraft operations: Corrective actions to orientation may be required by ground control;
possible changes in drag affect orbit predictions.
Other systems: HF radio propagation can fade at higher latitudes,
and aurora has been seen as low as New York and Idaho (typically 55° geomagnetic latitude.).
A UV index reading of 11 or more means extreme risk of harm from unprotected sun
exposure. Take all precautions because unprotected skin and eyes can burn in minutes.
Try to avoid sun exposure between 10 a.m. and 4 p.m. If outdoors, seek shade and wear sun
protective clothing, a wide-brimmed hat, and UV-blocking sunglasses. Generously apply broad
spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days, and after swimming or sweating.
Bright surfaces, such as sand, water, and snow, will increase UV exposure.