Conditions occurring during the winter and spring seasons – such as low temperatures, ice, snow and frost – may reduce the usability of aids to navigation. Aids to navigation may be off station, destroyed or damaged, and their lights may be unreliable or unlit. Aids to navigation may be temporarily replaced with virtual AIS AtoNs. After the winter season, the inspection of spar buoys and other buoys lasts several weeks. Vessels are advised to navigate with caution.
