LIST OF FIGURES
Figure 1.1: The number of ice-storm catastrophes in each climate region during 1949–
2000. Values in parentheses are those catastrophes that only occurred within the region.
Caption ad figure reproduced from Fig. 3 in Changnon (2003a).
Figure 1.2: The amount of loss (millions of dollars expressed in 2000 values) from icestorm catastrophes in each climate region during 1949–2000. Values in parentheses are
the average losses per catastrophe. Caption and figure reproduced from Fig. 2 in
Changnon (2003a).
Figure 1.3: Average number of hours per year with freezing rain in the United States.
Caption and figure reproduced from Fig. 1 in Houston and Changnon (2007).
Figure 1.4: Composite temperature and dewpoint profiles for freezing drizzle (ZL) and
freezing rain (ZR). The sample consists of 94 freezing rain and 127 freezing drizzle
rawinsonde observations from 48 stations between Oct 1972 and April 1976. Figure
reproduced from Fig. 1 in Bocchieri (1980).
Figure 1.5: Conceptual model of the transition region in a midlatitude winter storm.
Figure reproduced from Fig. 14 in Raga et al. (1991).
Figure 1.6: (a) Time-mean sea level pressure (heavy solid, interval of 4 hPa) and 1000–
500-hPa thickness (dashed, interval of 60 m) for the 5–9 Jan 1998 period. Time-mean
anomalies of (b) sea level pressure [heavy contours with interval of 4 hPa and solid
(dashed) for positive (negative) values], (c) 1000–500-hPa thickness [heavy contours
with interval of 60 m with solid (dashed) for positive (negative) values], and (d) 1000–
925-hPa thickness [heavy contours with interval of 7 m with solid (dashed) for positive
(negative) values]. Thickness anomaly contour intervals in (c) and (d) correspond to
approximately 3°C. Caption and figure reproduced from Fig. 2 in Gyakum and Roebber
(2001).
Figure 1.7: Paths of three parcel trajectories ending in the precipitation zone (194,400
km2 boxed region) during the 1998 ice storm. Tick marks indicate 12-hourly positions,
beginning with the noted start time. Figure reproduced from Fig. 8 in Gyakum and
Roebber (2001).
Figure 1.8: The encounter of continental polar (cP; blue arrows) with tropical
maritime (mT; red arrows) air masses to the east of Tibetan Plateau. The pink
oval marks the ice storm region. The thicker arrows indicate the dominant
directions in air mass movement. Caption and figure reproduced from Fig. 1 in Zhou et
al. (2011).
Figure 2.1: Surface map showing the location of all 225 stations (red dots) in the
freezing rain climatology. The elevation (meters above sea level) is shaded every 250 m.
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Figure 2.2: Map highlighting the 14 CWAs included in the ice storm climatology.
Figure 2.3: Archetypical surface synoptic weather patterns associated with freezing
precipitation east of the Rocky Mountains. Caption and figure reproduced from Fig. 2 in
Rauber et al. (2001b).
Figure 3.1: Average number of freezing rain hours per season (contoured every 5 h).
Figure 3.2: Average number of freezing rain hours during: (a) the Dec–Jan period and
(b) the Feb–Mar period (contoured every 5 h).
Figure 3.3: Time series of seasonal freezing rain hours at KALB.
Figure 3.4: Frequency distribution of seasonal freezing rain hours at KALB.
Figure 3.5: Average number of freezing rain events per season.
Figure 3.6: Average number of significant freezing rain events per season.
Figure 3.7: Percentage of total freezing rain events qualifying as significant (contoured
every 10%).
Figure 3.8: Mean freezing rain event duration (contoured every h).
Figure 3.9: Number of ice storms observed during each season.
Figure 3.10: Monthly distribution of ice storms during the 1993–2010 period.
Figure 3.11: Number of ice storms impacting each county during the 1993–2010 period.
Figure 3.12: Frequency distribution of ice storms by spatial coverage. Values in
parentheses indicate the corresponding number of ice storms.
Figure 3.13: Number of ice storms as a function of the number of CWAs impacted.
Figure 3.14: Distribution of total ice storms (blue) and synoptic ice storms (red) by event
type.
Figure 4.1: Composite 500-hPa geopotential height (contoured every 6 dam) and
anomalies (shaded every 30 m) for Type G events at: (a) t−48, (b) t−24, and (c) t0. Green
star denotes the approximate location of Albany, NY.
Figure 4.2: Composite 850–700-hPa layer-averaged wind (arrows, m s−1) and 0°C
isotherm (dashed), precipitable water (green, every 4 mm), and standardized precipitable
water anomalies (shaded, every 0.5 σ) for Type G events at: (a) t−48, (b) t−24, and (c) t0.
Green star denotes the approximate location of Albany, NY.
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Figure 4.3: Composite 300-hPa wind speed (shaded, every 5 m s−1), 1000–500-hPa
thickness (dashed, every 6 dam), and mean sea level pressure (black, every 4 hPa) for
Type G events at: (a) t−48, (b) t−24, and (c) t0. Green star denotes the approximate location
of Albany, NY. Red line in Fig. 4.3c marks the y–z cross section (extending from A to
A′) plotted in Fig. 4.5.
Figure 4.4: Composite 700-hPa temperature (dashed, every 3 K), Q-vectors (arrows,
10−11 K m−1 s−1), and RHS Q-vector form of QG omega equation (shaded, every 2.5 ×
10−16 K m−2 s−1) for Type G events at t0. Green star denotes the approximate location of
Albany, NY.
Figure 4.5: Composite cross section centered on Albany, NY, extending from 52.75°N,
73.80°W (A) to 32.75°N, 73.80°W (A′). Frontogenesis [shaded, every 1 K (100 km)−1 (3
h)−1], potential temperature (black, every 2 K), wind speed (green, every 5 m s−1), vertical
velocity (dashed red, every 5 μb s−1, only negative values plotted), and ageostrophic
circulation (arrows) for Type G events at t0. The top arrow is the reference vector for
horizontal ageostrophic motion, and the bottom arrow is the reference vector for vertical
motion. Red star denotes the approximate location of Albany, NY.
Figure 4.6: As in Fig. 4.1, except for Type BC events.
Figure 4.7: As in Fig. 4.2, except for Type BC events.
Figure 4.8: As in Fig. 4.3, except for Type BC events. Red line in Fig. 4.8c marks the y–
z cross section (extending from A to A′) plotted in Fig. 4.10.
Figure 4.9: As in Fig. 4.4, except for Type BC events.
Figure 4.10: As in Fig. 4.5, except for Type BC events.
Figure 5.1: Map highlighting the 149 counties impacted by the 3–4 Jan 1999 ice storm.
Figure 5.2: 300-hPa wind speed (shaded, every 5 m s−1), 1000–500-hPa thickness
(dashed, every 6 dam), and mean sea level pressure (black, every 4 hPa) at 1200 UTC 2
Jan 1999.
Figure 5.3: Precipitable water (shaded, every 4 mm), 850–700-hPa layer-averaged
equivalent potential temperature (white, every 10 K), and 850–700-hPa layer-averaged
moisture transport (arrows, expressed as the product of wind velocity and mixing ratio,
multiplied by 100) at 1200 UTC 2 Jan 1999.
Figure 5.4: As in Fig. 5.2, except at 0000 UTC 3 Jan 1999.
Figure 5.5: As in Fig. 5.3, except at 0000 UTC 3 Jan 1999.
Figure 5.6: As in Fig. 5.2, except at 1200 UTC 3 Jan 1999.
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Figure 5.7: As in Fig. 5.3, except at 1200 UTC 3 Jan 1999.
Figure 5.8: As in Fig. 5.2, except at 0000 UTC 4 Jan 1999.
Figure 5.9: As in Fig. 5.3, except at 0000 UTC 4 Jan 1999.
Figure 5.10: Mean sea level pressure (black, every 2 hPa) and 10-m streamlines (blue) at
0600 UTC 3 Jan 1999. Surface elevation is shaded every 200 m.
Figure 5.11: 2-m temperature (red, every 2°C) at 0600 UTC 3 Jan 1999. Surface
elevation is shaded every 200 m.
Figure 5.12: As in Fig. 5.10, except at 1800 UTC 3 Jan 1999.
Figure 5.13: As in Fig. 5.11, except at 1800 UTC 3 Jan 1999.
Figure 5.14: Skew-T with temperature (red, °C), dewpoint (blue, °C), and wind (barbs,
kt). Solid black, orange, and green lines denote constant values of temperature, potential
temperature, and equivalent potential temperature, respectively. Dashed green lines
denote constant values of mixing ratio. The 0°C isotherm is highlighted in purple. Based
on rawinsonde data from the 0000 UTC 3 Jan 1999 Pittsburgh, PA (PIT), sounding.
Figure 5.15: As in Fig. 5.14, except based on rawinsonde data from the 1200 UTC 3 Jan
1999 Albany, NY (ALB), sounding.
Figure 5.16: 120-h backward trajectories ending at 0600 UTC 3 Jan 1999 over
Pittsburgh, PA (PIT), which is denoted by the black star. Red, blue, and green lines
represent air parcels arriving 500 m, 1500 m, and 3000 m above ground level (AGL),
respectively. The top time series indicates the altitude of each parcel (m AGL), while the
bottom time series indicates the ambient potential temperature (K), at 6-h intervals.
Calculated from NCEP/NCAR reanalysis data.
Figure 5.17: As in Fig. 5.16, except for backward trajectories ending at 1800 UTC 3 Jan
1999 over Albany, NY (ALB).
Figure 5.18: Map highlighting the 74 counties impacted by the 11–12 Dec 2008 ice
storm.
Figure 5.19: Quantitative precipitation estimates valid for the 24-h period ending at 1200
UTC 12 Dec 2008. From the National Mosaic & Multi-sensor QPE.
Figure 5.20: As in Fig. 5.2, except at 0000 UTC 11 Dec 2008.
Figure 5.21: As in Fig. 5.3, except at 0000 UTC 11 Dec 2008.
Figure 5.22: As in Fig. 5.2, except at 1200 UTC 11 Dec 2008.
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Figure 5.23: As in Fig. 5.3, except at 1200 UTC 11 Dec 2008.
Figure 5.24: As in Fig. 5.2, except at 0000 UTC 12 Dec 2008.
Figure 5.25: As in Fig. 5.3, except at 0000 UTC 12 Dec 2008.
Figure 5.26: As in Fig. 5.2, except at 1200 UTC 12 Dec 2008.
Figure 5.27: As in Fig. 5.3, except at 1200 UTC 12 Dec 2008.
Figure 5.28: As in Fig. 5.10, except at 1800 UTC 11 Dec 2008.
Figure 5.29: As in Fig. 5.11, except at 1800 UTC 11 Dec 2008.
Figure 5.30: As in Fig. 5.10, except at 0600 UTC 12 Dec 2008.
Figure 5.31: As in Fig. 5.11, except at 0600 UTC 12 Dec 2008.
Figure 5.32: As in Fig. 5.14, except based on rawinsonde data from the 0000 UTC 12
Dec 2008 Albany, NY (ALB), sounding.
Figure 5.33: As in Fig. 5.14, except based on rawinsonde data from the 0600 UTC 12
Dec 2008 Gray, ME (GYX), sounding.
Figure 5.34: As in Fig. 5.16, except for backward trajectories ending at 0000 UTC 12
Dec 2008 over Albany, NY (ALB), and calculated from the NCEP Global Data
Assimilation System (GDAS) model.
Figure 5.35: As in Fig. 5.16, except for backward trajectories ending at 0600 UTC 12
Dec 2008 over Gray, ME (GYX), and calculated from the NCEP Global Data
Assimilation System (GDAS) model.
Figure 6.1: Conceptual model illustrating the synoptic-scale environment characteristic
of Type G events in the ALY CWA. Plotted features include the 500-hPa geopotential
height (solid black contours), 300-hPa wind speed (shaded; J denotes the jet maximum,
precipitable water (values > 25 mm shaded in green), 850–700-hPa 0°C isotherm (dashed
red contour), the surface 0°C isotherm (dashed magenta contour), and 850–700-hPa wind
vector (speeds > 20 m s−1). Concentrated regions of QG forcing for ascent and low-level
(925-hPa) frontogenesis are indicated by the closed orange and purple contours,
respectively. The “H” and “L” symbols represent relative maxima and minima in sea
level pressure, respectively, and the warm front symbol denotes the location of the
surface baroclinic zone.
Figure 6.2: Conceptual model illustrating the synoptic-scale environment characteristic
of Type BC events in the ALY CWA. Plotted features include the 500-hPa geopotential
height (solid black contours), 300-hPa wind speed (shaded; J1 denotes the primary jet
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maximum and J2 denotes the secondary jet maximum), precipitable water (values > 25
mm shaded in green), 850–700-hPa 0°C isotherm (dashed red contour), the surface 0°C
isotherm (dashed magenta contour), and 850–700-hPa wind vector (speeds > 20 m s−1).
Concentrated regions of QG forcing for ascent and low-level (925-hPa) frontogenesis are
indicated by the closed orange and purple contours, respectively. The “H” and “L”
symbols represent relative maxima and minima in sea level pressure, respectively, and
the warm front symbol denotes the location of the surface baroclinic zone.
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