Boundary County
Section 9
Hazard Profiles – Winter Storms
Definition, Description and
Potential Damage Winter storms
vary widely in size, duration, and intensity, but they are generally
characterized by low temperatures and blowing snow. These storms may impact a
single community or a multi-state area. They may last hours or days, drop a
small amount of snow or blanket an area in wet snow and ice.
A severe winter storm is defined
as one that drops four or more inches of snow during a twelve hour period, or
six or more inches during a twenty-four hour span. A blizzard is a winter storm
with winds exceeding thirty-five miles per hour and temperatures of 20° F or
lower. Strong winds can lower the effective temperature through "wind
chill." An ice storm occurs when water freezes immediately on contact with
the ground, structures, and vegetation. The
LEPC estimates that Boundary County experiences at least one severe winter storm
every year.
The principal hazards associated
with severe winter storms are:
·
Snow and/or ice accumulation
·
Extreme cold
·
Significant reduction of visibility
As frequently experienced in
Boundary County, especially in the higher elevations, heavy snow and/or ice can
block roads, break power lines, topple trees, and cause flooding, landslides or
avalanches. Trapped motorists may be stranded for prolonged periods and may
suffer injury or death if not prepared. Casualties
may result as unfit residents attempt to dig out their homes and driveways. Exhaustion
or heart attack is the second most likely cause of winter storm-related deaths.
Power outages can aggravate the extreme cold, leaving residents and livestock in
the cold and dark for days or threaten the safety of people dependent on
electricity for needed medical equipment.
In Boundary County, blocked
roads and limitations on access to emergency services is a concern.
Communities, such as Porthill, the Moyie River downstream from the Good
Grief resorts and Eastport are at least 25 miles and at least 50 minutes from
the nearest hospital. Road conditions can thwart efforts to get the seriously ill
or injured to needed services. In
addition, motorists who are ill equipped for road conditions may get stranded or
cause accidents. Accidents may
contribute to roadblocks and access problems for emergency service needs.
Although there are no documented
cases in Boundary County, extreme cold during winter storms can lead to
casualties, both directly, through hypothermia, and indirectly. Hypothermia is a
reduction of the body's core temperature due to prolonged exposure to cold. It
is not always fatal but can produce long-term ill effects in survivors. The
elderly are particularly at-risk. Frostbite (physical damage to bodily tissue
from exposure to extreme cold) is a secondary risk that can also cause permanent
damage.
Indirectly, extreme cold can
lead to casualties through improper use of makeshift heaters, such as charcoal
briquettes, in an enclosed space. Many fuels produce carbon monoxide that can
lead to asphyxiation and may cause structural fires if untended or
out-of-control. Fire control may be hampered by a freezing water supply and
reduced accessibility.
Cold may persist long after the
"storm" passes, complicating response and recovery functions.
Blowing snow and reduced sunlight during winter storms can make travel,
both walking and driving, dangerous. Transportation accidents (automobile and
other vehicles) are the leading cause of death during winter storms.
The impacts of a major storm may persist long after the event. Heavy snow can also cause structural damage to homes and businesses when the weight of snow causes roofs to fail. This is a common problem in Boundary County during major snow events. Recovery may take months when extensive property and economic damage has occurred.
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Severe Winter Storm Past Hazard Events and Risk
The occurrence of severe winter storms is to a large part dependent on broad
climatic trends. These trends are difficult to forecast and the assumptions
underlying projection of future events are subject to intense debate. It
is consequently difficult to generate any hard estimates of future storm
frequency or intensity. Boundary
County is rated as "Moderate Snowfall" or "Heavy Snowfall"
by FEMA.
Boundary County experienced
federally declared disaster events in February 1996 and in November 1996 through
January 1997. The winter of 1996
through 1997 was considered a record year for snowfall and heavy spring rain in
Boundary County. In November 1996,
Boundary County was declared a disaster area when many roofs on buildings in the
area collapsed or came dangerously close to collapsing from the usually heavy
snow. The Idaho National Guard was
called on to assist in snow removal from most of the downtown Bonners Ferry city
businesses and City Hall. The Guard
also assisted in removing snow from other buildings in the county, such as
public schools.
LEPC Relative Risk Rating
In the LEPC relative risk rating of hazards, Winter Storm was given a
moderate risk rating. The LEPC
estimates that, on the average, Boundary County experiences a “winter storm”
somewhere in the county once a year, but most snow storms are not considered to
be emergency incidents. Storms may
cause temporary road closures, school closures and delays.
Few injuries or illnesses are likely to occur during a severe winter
storm event and few properties can be expected to be destroyed.
However, many properties will be damaged, and environmental resources
will be damaged (with short-term recovery possible).
A single event will usually have a low direct cost but will have a
high indirect cost. There have been no recorded serious events since 1996-1997.
Highly Vulnerable Critical
Facilities The LEPC identified the
following “ “critical facilities” as highly vulnerable to winter storms:
Black Mountain repeater services
is the primary repeater for area law enforcement and most federal agencies.
This is also the location of the radio and television translators.
Verizon Communication also
houses a structure on Black Mountain for the Boundary County phone network.
WINTER STORM ACTION PLAN
MITIGATION ACTIONS
1.
Develop and update enforceable standardized building and planning codes.
Give special emphasis adequate roof load-bearing capability.
Lead
Agency:
Boundary County Building and Planning
Supporting
Agencies: LEPC, Boundary County Office of Emergency Management, Idaho Department
of Transportation, private property owners, property owner associations, and
interested community groups
When:
Annually
Resources/Funding:
Annual agency budgets
PUBLIC EDUCATION AND AWARENESS
1.
Educate the public on load-structured failure during snow events.
Lead
Agency:
Boundary County Building and Planning
Supporting
Agencies: Boundary County Sheriff’s Office, LEPC, Idaho Department of
Transportation, private property owners, interested community groups
When:
One year and then annually
Resources/Funding:
Annual agency budgets
2.
Develop and distribute information about building regulations and conduct
private structure inspections.
Lead
Agency:
Boundary County Planning and Zoning
Supporting
Agencies: Boundary County Building and Planning Department and other county,
state and federal agencies
When:
One year
Resources/Funding:
Federal and state grants, local budgets
EMERGENCY
SERVICES
1.
All winter storm incidents should be reported to the Office of Emergency
Management.
Lead
Agency:
Boundary County Office of Emergency Management
Supporting
Agencies: Local fire districts, local highway districts, LEPC
When:
Ongoing
Resources/Funding: FEMA and state disaster mitigation funds, county budget, fire and highway district budgets
2.
Plan for and maximize emergency access to all public and private property
during winter storm incidents.
Lead
Agency:
Boundary County Highway Districts
Supporting
Agencies: Boundary County
Sheriff’s Department, local highway Districts, Idaho State Department of
Transportation, Planning and Zoning
When:
Two to five years
Resources/Funding:
FEMA grants, local and state budgets
3.
Support initiatives to provide effective public communication during
winter storm incidents.
Lead
Agency:
Boundary County Office of Emergency Management
Supporting
Agencies: Natural Resource and
Conservation Service; US Geological Survey, National Weather Service, and local
elected officials
When:
Two to five years
Resources/Funding:
Agency budgets
4.
Identify and prioritize existing problems which could impact critical
infrastructures.
Lead
Agency:
LEPC
Supporting
Agency: Idaho
Transportation Department, and County Road and Bridge Departments
When:
Ongoing
Resources/Funding:
Local funding source