On a cold, blustery day, Denise Giardina's diary article {"Appalachian Winter," Outlook, Jan. 3} fired a shivering bolt of reality into the nation's capital. While most people equate the Appalachian coal fields with hard times, few understand the roots of their profound poverty and bleak future.

Denise Giardina removes the mythical coats that many well-off people and politicians like to comfort themselves in when discussing federal social programs. The perception that such programs only encourage lazy people to become lazier does not hold up with regard to the individuals whom Denise Giardina writes about. These are proud, hard-working people whose problems are a result of major events beyond their control.

Denise Giardina also dispels one of the greatest Appalachian myths of all times -- that a vibrant coal industry is the only socio-economic savior the region needs. Instead, she ironically points out that ''the root cause of the problem {is} a multinational energy industry which owns most of the land in the region, takes out the coal and leaves little in return save economic instability.''

Nevertheless, economic policy in the region continues to be based on incentives to make the coal industry stronger. The new naked truth, however, is found in the reality that the coal industry has produced more coal in 1987 than in any year in history, with approximately half the number of miners it employed in 1970.

Where is the coal-field wealth going? It leaves on the coal trains and is dumped into the accounts of huge energy companies in the great urban centers. Companies, by the way, are using the money to open new mines and energy ventures in foreign countries (Australia, Colombia, Brazil and China) that compete with U.S. jobs. Appalachia has always been a colony for the coal industry.

Appalachia's real savior is economic diversity. Unfortunately, it is difficult to attract outside businesses to an area plagued with scarred lands and polluted water by strip mining, a poorly educated population whose only meaningful jobs have been mining and closed political systems controlled by the coal industry.

Time is running out for parts of the coal fields. For seven years the Reagan administration has encouraged the nation to forget about its social and economic problems. Instead, the administration has encouraged the nation just to feel good about itself. Throwing a blanket over a festering sore may hide it for a while, but meanwhile it grows worse.

JAMES S. LYON

Director, Citizens Mining Project

Environmental Policy Institute

Washington