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 8 to 10 means very high risk of harm from unprotected sun exposure.
Take extra precautions because unprotected skin and eyes will be damaged and can burn quickly.
Minimize 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.
On the ground:
Wind felt on face; leaves rustle; ordinary vanes moved by wind.
On the sea:
Small wavelets, still short, but more pronounced. Crests have a glassy appearance and do not break.
On the ground:
Leaves and small twigs in constant motion; wind extends light flag.
On the sea:
Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered white horses.
A UV index reading of 3 to 5 means moderate risk of harm from unprotected sun exposure.
Stay in shade near midday when the sun is strongest. If outdoors, 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.