Chapter 16.54
VOLCANIC HAZARD AREA
Sections:
16.54.040 Relationship to framework ordinance.
16.54.010 Short title.
The ordinance codified in this chapter, together with any amendments, shall be known as the “Volcanic Hazard Area Ordinance.” (Ord. 1551 § 1 (part), 1992)
16.54.020 General authority.
This chapter is adopted under the authority of RCW 36.70A.050. (Ord. 1551 § 1 (part), 1992)
16.54.030 Purpose.
At over 14,410 feet high, Mount Rainier dominates the skyline of the southern Puget Sound region. This glacier-clad active volcano is capable of spewing ash from pyroclastic eruptions, and generating large volumes of lahars and floods which have, in the recent geologic past, inundated various watersheds and reached the shores of Puget Sound significantly altering pre-flood conditions. The purpose of this chapter is to regulate the use of land in and around volcanic hazard areas in order to protect lives, property, and public infrastructure; and to comply with the Washington State Growth Management Act. (Ord. 2071 § 28, 2003: Ord. 1551 § 1 (part), 1992)
16.54.040 Relationship to framework ordinance.
The provisions of this chapter shall apply in conjunction with SMC 16.40.030 through 16.40.200. (Ord. 1551 § 1 (part), 1992)
16.54.050 Applicability.
Volcanic hazard areas are areas within the city which show a likelihood of lahars, debris flows and related flooding associated with volcanic activity from Mt. Rainier. (Ord. 2071 § 29, 2003: Ord. 1551 § 1 (part), 1992)
16.54.060 Mapping.
A. Volcanic hazard areas are those areas that, in the recent geologic past, have been inundated by Case I or Case II lahars or other types of debris flows, according to a map showing Volcano Hazards from Mount Rainier, Washington: Pyroclastic-flow hazard zone and inundation zones for Case I, II, and III lahars, published by the U.S. Geological Survey, Revised 1998: USGS Open-File Report 98-428. Volcanic hazard areas also include areas that have not been affected recently, but could be affected by future such events. Volcanic hazard areas are classified into the following categories:
1. Inundation Zone for Case I Lahars. Areas that could be affected by cohesive lahars that originate as enormous avalanches of weak chemically altered rock from the volcano. Case I lahars can occur with or without eruptive activity. The average reoccurrence rate for Case I lahars on Mount Rainier is about 500 to 1,000 years.
2. Inundation Zone for Case II Lahars. Areas that could be affected by relatively large noncohesive lahars, which most commonly are caused by the melting of snow and glacier ice by hot rock fragments during an eruption, but which can also have a noneruptive origin. The average time interval between Case II lahars from Mount Rainier is near the lower end of the 100- to 500-year range, making these flows analogous to the so-called “100-year flood” commonly considered in engineering practice.
B. Time Travel Zones. The ability to evacuate people from within a volcanic hazard area correlates to the distance from the source of an event (i.e., those areas closest to the event will have less time to evacuate than those areas farther away from the source of an event) and the amount of time for evacuation from the public notification (via a warning alarm system) that a lahar event has occurred. The amount of time that is anticipated for a debris flow, lahar, flood, or avalanche (estimated at 100 million cubic feet of volume) to travel from either the source of the event or the point where the AFM alarm is sounded is classified into the time travel zones. The city of Sumner and the urban growth area boundary are within Time Travel Zone C identified on the Pierce County Volcanic Hazard Areas Map which is based on the Bulletin of Volcanology, Vol. 60, pp. 98-109, titled: An Empirical Method for Estimating Travel Times for Wet Volcanic Mass Flows by T.C. Pierson, 1998. Time Travel Zone C is described as follows:
1. Time Travel Zone C on the Nisqually and White River systems is that area greater than an estimated 1-1/2-hour travel distance and less than or equal to an estimated two-hour travel distance from the source of the event.
2. Time Travel Zone C on the Puyallup and Carbon River systems is that area greater than an estimated one-hour travel distance and less than or equal to a 1-1/2-hour travel distance from the point where the AFM alarm is sounded. (Ord. 2071 § 30, 2003: Ord. 1551 § 1 (part), 1992)
16.54.070 Title notification.
All activity in volcanic hazard areas shall be accompanied by the recording of a notice with the Pierce County auditor in the form set forth below:
VOLCANIC HAZARD AREA NOTICE
Parcel Number:__________________
Address:_______________________
Legal Description:________________ ______________________________
Notice: This site lies within a Volcanic Hazard Area as defined by Chapter 16.54, Sumner Municipal Code. The site was the subject of a development proposal for ___________________, Sumner application number ___ filed on__________________. Restrictions on use or alterations of the site may exist due to natural conditions of the site and resulting regulation. Review of such application has provided information on the location of a Volcanic Hazard Area and any restrictions on use.
Signature of owner(s)
(NOTARY ACKNOWLEDGEMENT)
(Ord. 1551 § 1 (part), 1992)
16.54.080 Plat notification.
For all proposed short subdivisions and subdivision proposals within volcanic hazard areas, the applicant shall include a note on the face of the plat as set forth below:
Notice: This site lies within a Volcanic Hazard Area as defined by the Sumner Municipal Code. Restrictions on use or alterations of the site may exist due to natural conditions of the site and resulting regulation.
(Ord. 1551 § 1 (part), 1992)
16.54.090 Regulations.
A. No critical facilities shall be constructed or located in volcanic hazard areas as set forth in SMC 16.54.060. Critical facilities are those listed below:
1. Hospitals;
2. Jails and detention facilities, excluding temporary holding cells in police stations;
3. Institutional or congregate care facilities for care of greater than 50 incapacitated patients;
4. All structures with occupant load of greater than 5,000 people as established by the International Building Code.
B. The applicant or property owner for a critical facility shall submit to the director, prior to occupancy of any critical facility, a written plan for evacuation of residents or occupants. The plan shall be approved by the city prior to final occupancy approval. The applicant or property owner shall also obtain and maintain a weather radio as approved by the National Oceanic and Atmospheric Administration (NOAA) for receiving notice of a lahar. (Ord. 2439 § 14, 2013; Ord. 2071 § 31, 2003: Ord. 1551 § 1 (part), 1992)