Read the passage and then answer the question.

In the northeastern United States and Canada, the year 1816 brought unusually cold conditions. A June snowstorm dumped thirty centimetres of snow in some areas. In July and August, temperatures fell below freezing—crops froze, and many people went hungry. Normal summer conditions never occurred. For years, scientists were baffled about what happened. Now, however, they believe that the cause was volcanic dust in the atmosphere. The previous year, far across the ocean, Indonesia’s Mt Tambora had erupted in an enormous explosion, shooting tonnes of ash and dust into the air. Scientists believe that this dust caused the sun’s rays to be reflected back into space, leading to the big chill.