Massachusetts-based Hanover Insurance Group has estimated the impact of its catastrophe losses to be in the range of $145 to $160m before tax for the second quarter of 2011.

The insurer said the it expects the loss to be $2.08 to $2.30 per share after tax.

Previously, the company the estimated catastrophe losses for the month of April to be between $70 and $85m before tax.

Hanover said quarterly loss estimates are primarily due to a series of tornadoes that affected Missouri and surrounding states at the end of May and to a lesser extent of damages due to tornadoes and wind damage on between May 31 – June 1 in Massachusetts.