EXHIBIT 15
 
September 29, 1998
 
IDACORP, Inc.
Boise, Idaho
 
    We have made a review, in accordance with standards established by the
American Institute of Certified Public Accountants, of the unaudited interim
financial information of Idaho Power Company and subsidiaries for the periods
ended March 31, 1998 and 1997 and June 30, 1998 and 1997, as indicated in our
reports dated May 8, 1998 and August 3, 1998, respectively; because we did not
perform an audit, we expressed no opinion on that information.
 
    We are aware that our reports referred to above, which were included in
Idaho Power Company's Quarterly Reports on Form 10-Q for the quarters ended
March 31, 1998 and June 30, 1998, are being used in this Registration Statement
of IDACORP, Inc., IDACORP Trust I, IDACORP Trust II and IDACORP Trust III on
Form S-3.
 
    We also are aware that the aforementioned reports, pursuant to Rule 436(c)
under the Securities Act of 1933, are not considered a part of the Registration
Statement prepared or certified by an accountant or a report prepared or
certified by an accountant within the meaning of Sections 7 and 11 of that Act.
 
DELOITTE & TOUCHE LLP
 
Boise, Idaho