The Arctic freeze that blasted across the U.S. last week pushed its chilly talons deep into the national economy. How far, farmers and commodities investors from Florida to Chicago are still trying to figure out. Some of the effects were as obvious as the icicles hanging from Sunbelt citrus fruit; others, like increased demand for energy supplies and bottlenecks in heating- fuel distribution, were harder to gauge. U.S. consumers, however, were fairly certain they could count on higher costs for food and fuel this winter.
In Florida, where the freeze was most brutal, growers who normally produce about 75% of the...