On March 4, 2020, Governor Newsom proclaimed a "state of emergency" pursuant to California's Emergency Services Act.  His proclamation reflected his finding that "conditions of Government Code section 8558(b), relating to the declaration of a State of Emergency, have been met". 

Section 8558(b) defines a "state of emergency" to mean:

"the duly proclaimed existence of conditions of disaster or of extreme peril to the safety of persons and property within the state caused by conditions such as . . . epidemic . . . which, by reason of their magnitude, are or are likely to be beyond the control of the services, personnel, equipment, and facilities of any single county, city and county, or city and require the combined forces of a mutual aid region or regions to combat, or with respect to regulated energy utilities, a sudden and severe energy shortage requires extraordinary measures beyond the authority vested in the California Public Utilities Commission."

The statute expressly refers to an "epidemic" but makes no reference to a "pandemic".  The two terms share the root "demic" which is derived from the Greek word, δημός, meaning the commons or people.  Δημός is also the source of the English words democracy and demagogue. 

The prefixes "epi" and "pan" are also derived from the Greek, meaning upon (ἐπί) and all (πᾶν), respectively.  According to the Centers for Disease Control, an epidemic is "an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area" and a pandemic is "an epidemic that has spread over several countries or continents, usually affecting a large number of people". 

While Section 8558(b) does not include pandemics among the list conditions that may give rise to a "state of emergency", this does not mean that a pandemic may not be a condition giving rise to a "state of emergency".  The legislature's use of "such as" makes it clear that the statutory list is non-exclusive.