Shares of building services group Northern Bear sank 10% after it warned profit for the year ending 31 March 2011 is expected to be below market expectations following the severe weather conditions at the end of 2010. The firm, which provides roofing, building and fire protection services, said that while trading conditions improved at the start of 2011, it was not enough to override losses in the previous few months."Trading conditions improved in January, and activity has increased further since that time. Whilst March was a very positive month, the markedly improved environment has not been sufficient to enable the company to trade in line with market expectations," Northern Bear said. CJ