2. Blizzard:
• temperatures usually -10oC or lower
• snow drifts caused by strong winds
• winds of at least 30 knots (55 km/hr)
Severe blizzard:
• temperatures of -12oC or lower
• winds of at least 40 knots (75 km/hr)
• visibility effectively zero.
3. Snowfalls in urban and metropolitan areas
Classification of the level of interruption
of normal socio-economic activities
(Rooney 1967):
• internal: restricted to the city
• external: between city and its region.
4. Classification of the level of interruption
of normal socio-economic activities
Level Interruption Description
Insignificant effects, no attention
V Minimal
from the mass media
Speed of traffic reduced,
IV Nuisance
some absences from school
Road accidents increase, risks for
III Inconvenience motorists, rural residents do not
come to town, etc.
Absenteeism, delays, road traffic
II Paralysis
accidents, abandoned vehicles
Emergency services at full alert,
Total
I closure of roads, schools,
paralysis
airports, etc.
5. The level of disruption of normal activities
caused by snowfall is related to...
...annual accumulations of snow:
• depth of accumulation
• the more snow falls in a year, the more
incidences of disrution at levels III-V
• level I disruption (total paralysis) is
not correlated with annual accumulation
• the more snowfalls occur, the greater
the level of municipal preparedness.
6. The level of disruption caused by snowfall
The impact of individual
snowstorms depends on:
• when they happen (day, hour)
• intensity of precipitation
• depth of snow accumulation
• wind speed.
7. The level of disruption caused by snowfall
• at higher temperatures snow
becomes denser and stickier
• if wind speeds exceed 25km/hr
the snow forms drifts.
8. Problem: a possible budget shortfall
• a year with more frequent snowfalls
• a year with heavy and prolonged storms
• big snowfalls at the end of
the season when the snow
clearance budget is used up.
9. Planning and funding the operations
• road salt and grit
• overtime payments to workers
• maintenance and repair of vehicles
• improvement and replacement of fleet
• costs of interruption of activities.
11. Snow emergency monitoring systems
• meteorological services
• road surveillance cameras
• field reports from operatives
• overflights (helicopter recce).
12. The planning process:-
• snowfall in relation to
transportation networks
• extent of snow disruption at
different altitudes above sea level.
13. "What if?" scenarios
...the snowfall occurs suddenly,
rapidly and with little or no warning?
...the snowfall occurs at the worst
possible time regarding socio-
economic activities (rush hour on
Friday just before Christmas)?.
14. "What if?" scenarios
...electricity supplies are
interrupted or hours or days?
...strong winds cause massive drifting?
...many people (or animals) are isolated?.
15. Who decides?
• e.g. on closures
Who monitors?
• e.g. meteorological and
road conditions
Who commands (whom)?
• e.g. on rescue,
on snow clearance
Who communicates?
• e.g. to mass media.
16. Co-ordination and diffusion
of information on closures
• transportation: roads,
railways, airports
• schools and colleges
• shops, offices, factories.
17. Role of the civil protection service
as a collector and disseminator of
information on the evolving situation
• risks
• closures
• advice on what to do
• radio and television links.
18. Some specific problems
• how to rescue stranded livestock
• delivery of urgent life-saving supplies
• urgent movement of sick & injured people
• where to hold heavy goods vehicles.
19. A question to answer:-
At what point does a snow emergency
cease to be a transient interruption
and become a serious problem of
business continuity management?.
20. Ice storms
• an accumulation of at least 0.64 cm
of ice on exposed surfaces
• precipitation at temperatures
that oscillate around 0oC
• roads and pavements very dangerous
• fall of branches from trees
• fall of pylons and utility poles.
21. Formation of precipitation at different altitudes a.s.l.
Altitude
3 km
Snow
2 km
Freezing rain
Sleet 1 km
Rain
-4 -2 0 2 4
Temperature (degrees C)
22.
23.
24.
25. Ice storm in SE Canada/NE USA
January 1998
• 80 hours of continuous freezing rain
• 1,000 pylons and 35,000 poles collapse
• millions of trees killed
• 150,000 people without electricity
for more than three weeks in Québec.
