Over Norwich, East Anglia, UK

The fibratus species of the high, ice-crystal clouds Cirrostratus and Cirrus (shown here) are when the clouds have been drawn out by the wind into long, fine filaments. These close strands of cloud appear rather like hair run through with a comb, and always form along the direction of the wind up at cloud level.

Full classification:

Other examples of fibratus:
Over San Antonio, Texas, US

Cirrostratus fibratus