The high prices Iowans are paying to heat their homes this winter are an “outrage” and are “disturbing,” according to Iowa Senator Tom Harkin. He’s calling today for a Congressional investigation into why natural gas prices have taken such extreme leaps in recent weeks.Natural gas demand has risen ten to 35-percent this winter, but the price has increased 200 to 400-percent. Harkin says Iowa’s largest utility raised natural gas prices in early January from 65-cents per therm to a dollar-five per therm. Harkin says it was a shock to the pocketbook for many Iowans.In calling for the investigation, Harkin says he’s asked several questions for which he wants the General Accounting Office to find answers, such as who’s profiting from the high prices.Harkin held a series of hearings in several Iowa cities last weekend to discuss the cost of natural gas and other forms of home heating.