In addition, being in the south, we frequently experience thunderstroms that sometimes have winds of 60mph or more. Another consideration that requires careful thought is the stability of the scope mounting. Since my primary interest is in astrophotography, I had to have an extremely solid mounting. In very cold climates, the soil can freeze to several inches deep and this would require the pier to be placed a bit deeper to keep the pier from moving due to the pressure of frozen soil. The type of soil at the site is another consideration.
Sand is more stable than clay soils and rocky soils have other requirements.
If not sure, consult an engineer familiar with conditions in your area. If the scope is only going to be used on an alt-azimuth mount, the pier could be of lesser construction than it would if used on a polar mount. Under these conditions, the pier is in compression on one side and tension on the other. I solved my problem of the ringing pier by pouring sand in the hollow pier and filling it almost to the top. Since sand has no natural harmonic frequency when not under compression, the problem was more or less solved.