|
This is a catalog of
California precipitation anomalies for
previous la Niña events based upon their strength and the
10 state hydrologic regions. It has the average for all
events, weak events, moderate events, strong and very strong events and the wide range
of the individual seasons that went into making up each of the averages.
It
cannot be stressed strongly enough that this is a climatological analysis
and NOT a forecasting tool. This is especially true for the averages of
different strength events which are made up of what are a very broad range
of conditions; some that are decidedly atypical.
The
Oceanic Niño Index (ONI)
is used to identify El Niño (warm) and La Niña (cool) events in the
tropical Pacific. The ONI is the running 3-month mean SST anomaly for the
Niño 3.4 region (i.e.,
5°N-5°S, 120°-170°W).
Events are defined as 5 consecutive months at or above the +0.5° anomaly
for warm (El Niño) events and at or below the -0.5 anomaly for cold (La
Niña) events. The threshold is further broken down into Weak (with a 0.5°
to 0.9° SST anomaly), Moderate (1.0° to 1.4°), Strong (1.5° to 1.9°) and Very Strong (≥
2.0°) events. For
the purpose of this report for an event to be weak, moderate, strong or
very strong it
much have equaled or exceeded the threshold for at least 3 months.
La Niña Events:
Weak: 1954-55,
1964-65,
1971-72, 1974-75, 1983-84, 1984-85, 2000-01, 2005-06, 2008-09, 2016-17,
2017-18
Moderate:
1955-56, 1970-71, 1995-96, 2011-12
Strong: 1973-74, 1975-76, 1988-89,
1998-99, 1999-00, 2007-08, 2010-11
|
|
|
All La Niña Events - Average Percent of Normal Seasonal
Precipitation (22 events) |
|
|
ENSO Type |
N Coast |
Sacramento |
N Lahontan |
SF Bay |
S Joaquin |
C Coast |
Tulare Lk |
S Lahontan |
S Coast |
Colo River |
|
All La NIña |
102% |
96% |
102% |
91% |
95% |
85% |
89% |
82% |
76% |
74% |
|
Weak La NIña |
97% |
94% |
102% |
90% |
97% |
85% |
89% |
89% |
77% |
85% |
|
Moderate La NIña |
115% |
105% |
110% |
102% |
97% |
86% |
91% |
67% |
73% |
53% |
|
Strong La NIña |
101% |
94% |
96% |
87% |
90% |
85% |
88% |
79% |
78% |
69% |
|
|
| ALL La Niña Events |
|
All La NIña |
|
All La Niña - Years by Percent of Normal Categories (22
events) |
|
|
|
|
% of Normal |
N Coast |
Sacramento |
N Lahontan |
SF Bay |
S Joaquin |
C Coast |
Tulare Lk |
S Lahontan |
S Coast |
Colo River |
|
<80% |
6 |
9 |
7 |
10 |
9 |
11 |
9 |
13 |
15 |
15 |
|
80-100% |
5 |
4 |
4 |
5 |
3 |
5 |
8 |
6 |
5 |
4 |
|
100-120% |
7 |
4 |
6 |
3 |
6 |
4 |
3 |
0 |
1 |
1 |
|
120-140% |
2 |
4 |
3 |
3 |
2 |
2 |
0 |
3 |
1 |
1 |
|
>140% |
2 |
1 |
2 |
1 |
2 |
0 |
2 |
0 |
0 |
1 |
|
Average -
ALL La Niña
ONI
≤
-0.5
 |
| 1954-55 |
1955-56 |
1964-65 |
1970-71 |
 |
 |
 |
 |
| 1971-72 |
1973-74 |
1974-75 |
1975-76 |
 |
 |
 |
 |
| 1983-84 |
1984-85 |
1988-89 |
1995-96 |
 |
 |
 |
 |
| 1998-99 |
1999-00 |
2000-01 |
2005-06 |
 |
 |
 |
 |
| 2007-08 |
2008-09 |
2010-11 |
2011-12 |
 |
 |
 |
 |
| 2016-17 |
2017-18 |
|
|
 |
 |
|
|
|
|
| WEAK La Niña Events |
|
Weak La NIña |
|
Weak La Niña - Years by Percent of Normal Categories (11
events) |
|
|
|
% of Normal |
N Coast |
Sacramento |
N Lahontan |
SF Bay |
S Joaquin |
C Coast |
Tulare Lk |
S Lahontan |
S Coast |
Colo River |
|
<80% |
5 |
6 |
4 |
6 |
5 |
6 |
4 |
4 |
6 |
6 |
|
80-100% |
1 |
1 |
2 |
2 |
1 |
2 |
4 |
5 |
4 |
2 |
|
100-120% |
3 |
2 |
3 |
1 |
3 |
2 |
2 |
0 |
1 |
1 |
|
120-140% |
1 |
1 |
1 |
1 |
1 |
1 |
0 |
2 |
0 |
1 |
|
>140% |
1 |
1 |
1 |
1 |
1 |
0 |
1 |
0 |
0 |
1 |
|
Average -
WEAK El Niño
ONI
≤
-0.5 to -0.9
 |
| 1954-55 |
1964-65 |
1971-72 |
1974-75 |
|
|
|
|
|
| 1983-84 |
1984-85 |
2000-01 |
2005-06 |
|
|
|
|
|
| 2008-09 |
2016-17 |
2017-18 |
|
|
|
|
|
|
|
|
| MODERATE La Niña Events |
|
Moderate La NIña |
|
Moderate La Niña - Years by Percent of Normal Categories
(4 events) |
|
|
|
% of Normal |
N Coast |
Sacramento |
N Lahontan |
SF Bay |
S Joaquin |
C Coast |
Tulare Lk |
S Lahontan |
S Coast |
Colo River |
|
<80% |
0 |
1 |
1 |
1 |
1 |
2 |
1 |
4 |
4 |
4 |
|
80-100% |
1 |
0 |
0 |
1 |
1 |
1 |
2 |
0 |
0 |
0 |
|
100-120% |
2 |
2 |
1 |
1 |
1 |
1 |
1 |
0 |
0 |
0 |
|
120-140% |
1 |
1 |
2 |
1 |
1 |
0 |
0 |
0 |
0 |
0 |
|
>140% |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
|
Average -
MODERATE El Niño
ONI
≤
-1.0 to 1.5
 |
| 1955-56 |
1970-71 |
1995-96 |
2011-12 |
|
|
|
|
|
|
|
|
| STRONG La Niña Events |
|
Strong La NIña |
|
Strong La Niña - Years by Percent of Normal Categories (7
events) |
|
|
| % of Normal |
N Coast |
Sacramento |
N Lahontan |
SF Bay |
S Joaquin |
C Coast |
Tulare Lk |
S Lahontan |
S Coast |
Colo River |
|
<80% |
1 |
2 |
2 |
3 |
3 |
3 |
4 |
5 |
5 |
5 |
|
80-100% |
3 |
3 |
2 |
2 |
1 |
2 |
2 |
1 |
1 |
2 |
|
100-120% |
2 |
0 |
2 |
1 |
2 |
1 |
0 |
0 |
0 |
0 |
|
120-140% |
0 |
2 |
0 |
1 |
0 |
1 |
0 |
1 |
1 |
0 |
|
>140% |
1 |
0 |
1 |
0 |
1 |
0 |
1 |
0 |
0 |
0 |
|
Average -
STRONG El Niño
ONI
≤
-1.5 TO -2.0
 |
| 1973-74 |
1975-76 |
1988-89 |
1998-99 |
|
|
|
|
|
| 1999-00 |
2007-08 |
2010-11 |
|
|
|
|
|
|
|
|
Percent of Normal (1981-2010) Rainfall for All Years |
| |
Normal |
54.75 |
37.71 |
19.66 |
26.37 |
28.72 |
20.86 |
16.88 |
7.43 |
18.39 |
5.49 |
| ENSO
Type |
Rainfall Season |
N Coast |
Sacramento |
N Lahontan |
SF Bay |
S Joaquin |
C Coast |
Tulare Lk |
S Lahontan |
S Coast |
Colo River |
| |
1950-1951 |
110% |
109% |
115% |
105% |
118% |
73% |
94% |
66% |
54% |
49% |
| Mod.
El Niño |
1951-1952 |
118% |
126% |
131% |
130% |
129% |
136% |
136% |
138% |
161% |
151% |
| Weak
El Niño |
1952-1953 |
115% |
101% |
97% |
92% |
82% |
75% |
83% |
67% |
70% |
74% |
| Weak
El Niño |
1953-1954 |
106% |
90% |
79% |
74% |
81% |
76% |
83% |
75% |
90% |
72% |
| Weak
La Niña |
1954-1955 |
71% |
67% |
65% |
70% |
75% |
78% |
79% |
67% |
73% |
65% |
| Mod.
La Niña |
1955-1956 |
138% |
132% |
139% |
130% |
130% |
109% |
117% |
79% |
80% |
62% |
| |
1956-1957 |
89% |
82% |
89% |
73% |
80% |
71% |
78% |
67% |
77% |
52% |
| Stg.
El Niño |
1957-1958 |
146% |
140% |
126% |
151% |
131% |
159% |
142% |
121% |
156% |
127% |
| Weak
El Niño |
1958-1959 |
80% |
69% |
71% |
56% |
61% |
62% |
53% |
56% |
50% |
52% |
| |
1959-1960 |
87% |
80% |
70% |
74% |
74% |
70% |
68% |
64% |
68% |
95% |
| |
1960-1961 |
97% |
78% |
67% |
64% |
61% |
53% |
58% |
55% |
37% |
47% |
| |
1961-1962 |
80% |
85% |
95% |
81% |
93% |
106% |
106% |
98% |
111% |
74% |
| |
1962-1963 |
115% |
119% |
132% |
120% |
109% |
102% |
96% |
69% |
53% |
42% |
| Mod.
El Niño |
1963-1964 |
80% |
67% |
81% |
61% |
69% |
62% |
72% |
75% |
76% |
90% |
| Weak
La Niña |
1964-1965 |
116% |
110% |
118% |
101% |
116% |
94% |
103% |
86% |
79% |
78% |
| Stg.
El Niño |
1965-1966 |
88% |
73% |
78% |
73% |
73% |
78% |
73% |
104% |
117% |
116% |
| |
1966-1967 |
107% |
120% |
131% |
134% |
133% |
133% |
142% |
102% |
130% |
72% |
| |
1967-1968 |
78% |
75% |
78% |
70% |
65% |
61% |
66% |
84% |
77% |
97% |
| Mod.
El Niño |
1968-1969 |
120% |
127% |
142% |
126% |
153% |
168% |
180% |
150% |
174% |
104% |
| Weak
El Niño |
1969-1970 |
110% |
110% |
111% |
99% |
96% |
74% |
77% |
57% |
59% |
73% |
| Mod.
La Niña |
1970-1971 |
118% |
103% |
116% |
92% |
87% |
78% |
82% |
72% |
77% |
55% |
| Weak
La Niña |
1971-1972 |
95% |
68% |
79% |
51% |
64% |
48% |
52% |
57% |
51% |
58% |
| Stg.
El Niño |
1972-1973 |
90% |
107% |
97% |
135% |
111% |
139% |
129% |
118% |
120% |
111% |
| Stg.
La Niña |
1973-1974 |
150% |
134% |
110% |
122% |
109% |
107% |
98% |
69% |
78% |
57% |
| Weak
La Niña |
1974-1975 |
100% |
95% |
98% |
92% |
101% |
95% |
91% |
84% |
86% |
63% |
| Stg.
La Niña |
1975-1976 |
68% |
49% |
57% |
39% |
49% |
43% |
56% |
67% |
61% |
77% |
| Weak
El Niño |
1976-1977 |
41% |
43% |
69% |
46% |
47% |
66% |
63% |
102% |
84% |
112% |
| Weak
El Niño |
1977-1978 |
128% |
133% |
120% |
134% |
140% |
169% |
170% |
190% |
212% |
199% |
| |
1978-1979 |
73% |
80% |
80% |
83% |
97% |
97% |
101% |
116% |
129% |
143% |
| Weak
El Niño |
1979-1980 |
107% |
114% |
130% |
120% |
121% |
123% |
127% |
152% |
178% |
192% |
| |
1980-1981 |
74% |
74% |
77% |
65% |
69% |
75% |
73% |
73% |
60% |
65% |
| |
1981-1982 |
143% |
145% |
146% |
157% |
149% |
118% |
124% |
110% |
103% |
91% |
| V.
Stg. El Niño |
1982-1983 |
155% |
163% |
159% |
187% |
180% |
196% |
186% |
190% |
195% |
187% |
| Weak
La Niña |
1983-1984 |
117% |
108% |
118% |
93% |
104% |
74% |
88% |
98% |
70% |
134% |
| Weak
La Niña |
1984-1985 |
78% |
70% |
80% |
79% |
73% |
70% |
80% |
128% |
83% |
146% |
| |
1985-1986 |
111% |
126% |
140% |
131% |
131% |
119% |
130% |
110% |
117% |
110% |
| Mod.
El Niño |
1986-1987 |
78% |
64% |
66% |
58% |
58% |
61% |
67% |
81% |
62% |
87% |
| Stg.
El Niño |
1987-1988 |
78% |
72% |
62% |
67% |
63% |
75% |
79% |
101% |
95% |
116% |
| Stg.
La Niña |
1988-1989 |
89% |
86% |
95% |
66% |
71% |
54% |
71% |
64% |
60% |
62% |
| |
1989-1990 |
74% |
76% |
76% |
64% |
73% |
54% |
63% |
50% |
56% |
45% |
| |
1990-1991 |
63% |
67% |
78% |
66% |
72% |
87% |
81% |
94% |
95% |
113% |
| Stg.
El Niño |
1991-1992 |
67% |
71% |
62% |
81% |
71% |
98% |
77% |
132% |
123% |
164% |
| |
1992-1993 |
118% |
125% |
123% |
123% |
131% |
145% |
136% |
160% |
206% |
213% |
| |
1993-1994 |
62% |
63% |
64% |
65% |
60% |
70% |
71% |
53% |
73% |
65% |
| Mod.
El Niño |
1994-1995 |
139% |
161% |
162% |
150% |
156% |
176% |
161% |
145% |
174% |
137% |
| Mod.
La Niña |
1995-1996 |
119% |
115% |
124% |
119% |
109% |
97% |
98% |
67% |
71% |
32% |
| |
1996-1997 |
119% |
117% |
132% |
104% |
123% |
107% |
120% |
79% |
86% |
49% |
| V.
Stg. El Niño |
1997-1998 |
145% |
158% |
128% |
173% |
152% |
203% |
179% |
180% |
198% |
169% |
| Stg.
La Niña |
1998-1999 |
111% |
96% |
109% |
90% |
89% |
80% |
79% |
74% |
54% |
60% |
| Stg.
La Niña |
1999-2000 |
93% |
97% |
86% |
98% |
100% |
100% |
90% |
70% |
69% |
54% |
| Weak
La Niña |
2000-2001 |
58% |
65% |
54% |
72% |
75% |
103% |
81% |
89% |
89% |
82% |
| |
2001-2002 |
93% |
86% |
76% |
89% |
82% |
63% |
76% |
41% |
32% |
25% |
| Mod.
El Niño |
2002-2003 |
111% |
104% |
90% |
103% |
89% |
96% |
94% |
92% |
105% |
76% |
| |
2003-2004 |
92% |
90% |
82% |
81% |
73% |
66% |
71% |
87% |
60% |
93% |
| Weak
El Niño |
2004-2005 |
98% |
108% |
108% |
122% |
130% |
151% |
132% |
187% |
209% |
212% |
| Weak
La Niña |
2005-2006 |
135% |
138% |
135% |
134% |
129% |
111% |
119% |
99% |
86% |
72% |
| Weak
El Niño |
2006-2007 |
78% |
61% |
57% |
56% |
56% |
40% |
48% |
35% |
29% |
30% |
| Stg.
La Niña |
2007-2008 |
83% |
70% |
73% |
74% |
71% |
83% |
72% |
81% |
88% |
82% |
| Weak
La Niña |
2008-2009 |
75% |
79% |
81% |
76% |
83% |
64% |
71% |
74% |
66% |
83% |
| Mod.
El Niño |
2009-2010 |
102% |
95% |
90% |
107% |
103% |
111% |
108% |
99% |
109% |
117% |
| Stg.
La Niña |
2010-2011 |
115% |
124% |
141% |
118% |
145% |
130% |
147% |
129% |
136% |
96% |
| Mod.
La Niña |
2011-2012 |
87% |
71% |
62% |
67% |
62% |
61% |
65% |
52% |
64% |
61% |
| |
2012-2013 |
83% |
78% |
83% |
71% |
67% |
54% |
47% |
53% |
48% |
78% |
| |
2013-2014 |
57% |
56% |
65% |
53% |
50% |
39% |
43% |
54% |
45% |
63% |
| Weak
El Niño |
2014-2015 |
82% |
74% |
84% |
79% |
57% |
59% |
51% |
65% |
58% |
86% |
| V.
Stg. El Niño |
2015-2016 |
112% |
104% |
121% |
95% |
103% |
82% |
98% |
96% |
72% |
74% |
| Weak
La Niña |
2016-2017 |
150% |
156% |
185% |
159% |
168% |
138% |
146% |
134% |
115% |
115% |
| Weak
La Niña |
2017-2018 |
75% |
76% |
108% |
69% |
77% |
61% |
65% |
60% |
43% |
37% |
| ENSO
Type |
Rainfall Season |
N Coast |
Sacramento |
N Lahontan |
SF Bay |
S Joaquin |
C Coast |
Tulare Lk |
S Lahontan |
S Coast |
Colo River |
|
