EXHIBIT 24 POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ Richard S. DeVine Director - ----------------------------- Richard S. DeVine POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ Jack Fabulich Director - ----------------------------- Jack Fabulich POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ Jonathan Fine Director - ----------------------------- Jonathan Fine POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ John P. Folsom Director - ----------------------------- John P. Folsom POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ Margel S. Gallagher Director - ----------------------------- Margel S. Gallagher POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ John A. Halleran Director - ----------------------------- John A. Halleran POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ Thomas L. Matson Director - ----------------------------- Thomas L. Matson POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ John H. Powell Director - ----------------------------- John H. Powell POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ Robert E. Quoidbach Director - ----------------------------- Robert E. Quoidbach POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ Donald Rodman Director - ----------------------------- Donald Rodman POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ Frank H. Russell Director - ----------------------------- Frank H. Russell POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ Sidney R. Snyder Director - ----------------------------- Sidney R. Snyder POWER OF ATTORNEY The director of Columbia Banking System, Inc. (the "Company"), whose signature appears below, hereby appoints W. W. Philip and J. James Gallagher, or either of them, as his attorney to sign, in his name and behalf and in any and all capacities stated below, the Company's Form 10-K Annual Report pursuant to Section 13 of the Securities Exchange Act of 1934, and likewise to sign any and all amendments and other documents relating thereto as shall be necessary, such person hereby granting to each such attorney power to act with or without the other and full power of substitution and revocation, and hereby ratifying all that any such attorney or his substitute may do by virtue hereof. This Power of Attorney has been signed by the following person in the capacity indicated, on the 25 day of February, 1998. Signature Title /s/ James M. Will Director - ----------------------------- James M. Will